Every day it seems that people are coming up with new and innovative ways to use mobile devices like cellphones and smart phones. Researchers at Princeton University are looking for new ways to measure a person's sense of _ with mobile devices. To gain a better understanding of how cellphones and other mobile devices can measure our sense of happiness, the research team conducted a study that was published recently in the journal Demography. To gather data for their study, the team created an application for mobile devices using the Android operating system. Once the app was developed, the researchers invited people to download it and take part in their study. Over a three-week period, the research team was able to collect data from some 270 participants living in 13 countries. Participants came not only from the United States, but also from other nations like Australia, Canada, China, France, Germany, Israel, Japan, Norway, South Korea, Spain, Sweden and the United Kingdom. Over the course of the study, participants received occasional text questions from the researchers that asked "How happy are you?". Along with recording their response, the app used the mobile device's built-in GPS to keep track of the participant's location. The study participants were asked to rate their current state of happiness on a scale of zero to five. As they gathered data from the information collected through the application, the researchers then were able to create new methods that could help provide a better understanding of how our surroundings can influence our emotional well-being. The researchers learned that mobile devices can provide an effective way to quickly grab information that, because of today's active lifestyle, can be difficult to record. Being able to quickly grab this information was something the researchers felt was important. They said feelings and emotions that were recorded as they were happening were most likely to be more honest and precise than using other methods like writing down how they felt on a piece of paper after the fact. What did the researchers find vital as to rate people's sense of happiness from the passage?
Recording people's feelings and emotions quickly. Writing down how they felt on a piece of paper. Answering the text question "How happy are you?" Knowing how the surroundings affect people's happiness.
Question: Every day it seems that people are coming up with new and innovative ways to use mobile devices like cellphones and smart phones. Researchers at Princeton University are looking for new ways to measure a person's sense of _ with mobile devices. To gain a better understanding of how cellphones and other mobile devices can measure our sense of happiness, the research team conducted a study that was published recently in the journal Demography. To gather data for their study, the team created an application for mobile devices using the Android operating system. Once the app was developed, the researchers invited people to download it and take part in their study. Over a three-week period, the research team was able to collect data from some 270 participants living in 13 countries. Participants came not only from the United States, but also from other nations like Australia, Canada, China, France, Germany, Israel, Japan, Norway, South Korea, Spain, Sweden and the United Kingdom. Over the course of the study, participants received occasional text questions from the researchers that asked "How happy are you?". Along with recording their response, the app used the mobile device's built-in GPS to keep track of the participant's location. The study participants were asked to rate their current state of happiness on a scale of zero to five. As they gathered data from the information collected through the application, the researchers then were able to create new methods that could help provide a better understanding of how our surroundings can influence our emotional well-being. The researchers learned that mobile devices can provide an effective way to quickly grab information that, because of today's active lifestyle, can be difficult to record. Being able to quickly grab this information was something the researchers felt was important. They said feelings and emotions that were recorded as they were happening were most likely to be more honest and precise than using other methods like writing down how they felt on a piece of paper after the fact. What did the researchers find vital as to rate people's sense of happiness from the passage?
A. Recording people's feelings and emotions quickly.
B. Writing down how they felt on a piece of paper.
C. Answering the text question "How happy are you?"
D. Knowing how the surroundings affect people's happiness.
Answer: