My bike was a three-speed English "racer", purchased during my second year in college in November 1964 for $44. Most of the money was earned by myself in my spare time, but I had to get my mother to help me out a little. At that time, bikes were rare on a college campus. My reason for getting a bicycle was a little strange. A friend of mine convinced me to take a summer job selling door-to-door and suggested that I should use a bicycle to travel between houses. The job didn't work out, but was in my brain. That fall, I borrowed another student's bike and rode 45 miles on the first day, but his bike soon had a flat  which he didn't like fixing. So I had to buy one. I immediately started using mine almost every day. Before getting the bike, I sometimes walked 28 miles to my parents' house. Now the bike gave me a quicker method, but my first trip took four hours due to strong headwinds that had me fight for every foot. Once I made a trip of 100 miles in one day. I decided to use the bike to go camping in the Smokies. During the trip, I recognized the need for handlebars and more gears, so I bought a ten-speed after just one year though I loved this bike. The first bike "hung around" for a couple of years, and then I gave it to my sister's kids who let it become part of their lives. We can infer that besides studying at college the writer    _   .
often helped his friend do business also worked in a factory had part-time jobs in his spare time had to make money to pay for his tuition
Question: My bike was a three-speed English "racer", purchased during my second year in college in November 1964 for $44. Most of the money was earned by myself in my spare time, but I had to get my mother to help me out a little. At that time, bikes were rare on a college campus. My reason for getting a bicycle was a little strange. A friend of mine convinced me to take a summer job selling door-to-door and suggested that I should use a bicycle to travel between houses. The job didn't work out, but was in my brain. That fall, I borrowed another student's bike and rode 45 miles on the first day, but his bike soon had a flat  which he didn't like fixing. So I had to buy one. I immediately started using mine almost every day. Before getting the bike, I sometimes walked 28 miles to my parents' house. Now the bike gave me a quicker method, but my first trip took four hours due to strong headwinds that had me fight for every foot. Once I made a trip of 100 miles in one day. I decided to use the bike to go camping in the Smokies. During the trip, I recognized the need for handlebars and more gears, so I bought a ten-speed after just one year though I loved this bike. The first bike "hung around" for a couple of years, and then I gave it to my sister's kids who let it become part of their lives. We can infer that besides studying at college the writer    _   .
A. often helped his friend do business
B. also worked in a factory
C. had part-time jobs in his spare time
D. had to make money to pay for his tuition
Answer: