When I was six years old, my mom told me that I could find anyone's number in the phone book. I used to look through the phone book for hours trying to find Michael Jordan's phone number. When I couldn't find it, I just dialed seven numbers. When someone answered, I'd ask, "Is that Michael Jordan?" Obviously, I always had the wrong number. A year later I started playing basketball at my local recreation center. It was very big. I never thought in my wildest dreams that a basketball court could be inside a building. The recreation center had a special smell in it, sort of like hot rubber. I guessed it was from the shoes hitting the floor so fast and hard. The atmosphere on the court was carefree. Our biggest excitement of the day was when we actually made a shot. We celebrated wins over ice cream at a fast food restaurant. I got good at it, and my confidence grew. I played it all the time until the sixth grade. As soon as junior high school came, I stopped playing basketball and focused on school. When senior high school started, I tried out for the school team and made it. We worked hard. Every week we did 300 push-ups and 300 sit-ups on our own. Our coach encouraged the sit-ups to keep stomach power, because it gave us so much control when we were playing basketball. If we didn't want to do the sit-ups and push-ups, we could practice dribbling   and shooting more. It's just us, the ball, the court and the net. But don't take my word for it. See for yourself. After all, I'm just one kid playing the game. The author's coach encouraged them to do sit-ups because   _  .
it is the basic preparation to play basketball it is more useful than dribbling and shooting it is the only way to make people stronger it helps keep stomach power
Question: When I was six years old, my mom told me that I could find anyone's number in the phone book. I used to look through the phone book for hours trying to find Michael Jordan's phone number. When I couldn't find it, I just dialed seven numbers. When someone answered, I'd ask, "Is that Michael Jordan?" Obviously, I always had the wrong number. A year later I started playing basketball at my local recreation center. It was very big. I never thought in my wildest dreams that a basketball court could be inside a building. The recreation center had a special smell in it, sort of like hot rubber. I guessed it was from the shoes hitting the floor so fast and hard. The atmosphere on the court was carefree. Our biggest excitement of the day was when we actually made a shot. We celebrated wins over ice cream at a fast food restaurant. I got good at it, and my confidence grew. I played it all the time until the sixth grade. As soon as junior high school came, I stopped playing basketball and focused on school. When senior high school started, I tried out for the school team and made it. We worked hard. Every week we did 300 push-ups and 300 sit-ups on our own. Our coach encouraged the sit-ups to keep stomach power, because it gave us so much control when we were playing basketball. If we didn't want to do the sit-ups and push-ups, we could practice dribbling   and shooting more. It's just us, the ball, the court and the net. But don't take my word for it. See for yourself. After all, I'm just one kid playing the game. The author's coach encouraged them to do sit-ups because   _  .
A. it is the basic preparation to play basketball
B. it is more useful than dribbling and shooting
C. it is the only way to make people stronger
D. it helps keep stomach power
Answer: