Carla Is the Fastest Runner on Her Track Team and Is

Multiple Choice

Carla is the fastest runner on her track team and is expected to win every race in which she competes this year. Barbara is also a very fast runner and has occasionally beaten Carla in practice times. Recently, their track coach decided that Carla and Barbara should stop racing each other in practices in order to increase the chances they will succeed on race days.
Which of the following would help justify the coach's reasoning?

A) Whenever Barbara beats Carla her confidence improves and makes her more likely to succeed on race day.
B) Carla and Barbara sometimes strain themselves by racing too hard during practice.
C) Carla and Barbara's race times have improved since they began challenging each other.
D) Carla often challenges Barbara to race, but Barbara prefers to take practice time more leisurely.
E) Carla is starting to lose against Barbara more often.