Fahad Azad, an engineer in India, invented a robot named DuctBot.The toy-car sized DuctBot measured 23 centimeters in length, 19 centimeters in width and 9 centimeters in height and weighs just two kilograms. The robot is designed to snake through dark, narrow air conditioning ducts   and clean them.A pair of LEDs fitted on the robot light up the dirty scenery, so _ can be captured   by a camera. In order to control it more easily, Mr. Azad chooses to fix DuctBot on wheels.The robot can clean off lots of dirt, as well as dead pigeons and insects.Keeping indoor air in good quality and monitoring carbon-dioxide levels in buildings with central air conditioning is a challenge.It is important in some places where clean air can mean a difference between life and death, such as hospitals.Dirty air has a bad influence on people's health. EPSCO, a Dubai-based company which specializes in improving indoor air quality, read about Mr. Azad's invention in a national newspaper after he had won an international robotics competition.EPSCO had cleaning equipment, but it needed someone to get into those ducts to do the dirty, dangerous work.Across India, for example, the task still falls to children.They are small enough to go through those ducts. In 2005, Mr. Azad who was still at university decided to do something about it.Six years later his own company, Robosoft Systems, has Bluestar, EPSCO and the Indian Navy, some leading air condition makers, as partners. Mr. Azad and his ten employees are currently exploring robot designs to examine oil tanks or sewage  pipes.Their biggest challenge is to make the robots user-friendly enough.Mr. Azad hopes that the robot could eventually be operated not by engineers but by workers.There will be lots of difficulties they need to overcome in the future. What can the Ductbot do for us?
Clean off the dirt in the ducts. Control the central conditioning. Reduce carbon-dioxide in buildings. Protect more animals in city.
Question: Fahad Azad, an engineer in India, invented a robot named DuctBot.The toy-car sized DuctBot measured 23 centimeters in length, 19 centimeters in width and 9 centimeters in height and weighs just two kilograms. The robot is designed to snake through dark, narrow air conditioning ducts   and clean them.A pair of LEDs fitted on the robot light up the dirty scenery, so _ can be captured   by a camera. In order to control it more easily, Mr. Azad chooses to fix DuctBot on wheels.The robot can clean off lots of dirt, as well as dead pigeons and insects.Keeping indoor air in good quality and monitoring carbon-dioxide levels in buildings with central air conditioning is a challenge.It is important in some places where clean air can mean a difference between life and death, such as hospitals.Dirty air has a bad influence on people's health. EPSCO, a Dubai-based company which specializes in improving indoor air quality, read about Mr. Azad's invention in a national newspaper after he had won an international robotics competition.EPSCO had cleaning equipment, but it needed someone to get into those ducts to do the dirty, dangerous work.Across India, for example, the task still falls to children.They are small enough to go through those ducts. In 2005, Mr. Azad who was still at university decided to do something about it.Six years later his own company, Robosoft Systems, has Bluestar, EPSCO and the Indian Navy, some leading air condition makers, as partners. Mr. Azad and his ten employees are currently exploring robot designs to examine oil tanks or sewage  pipes.Their biggest challenge is to make the robots user-friendly enough.Mr. Azad hopes that the robot could eventually be operated not by engineers but by workers.There will be lots of difficulties they need to overcome in the future. What can the Ductbot do for us?
A. Clean off the dirt in the ducts.
B. Control the central conditioning.
C. Reduce carbon-dioxide in buildings.
D. Protect more animals in city.
Answer: