Peterson, the current world record holder in the women' s 100-meter backstroke, has ranked first in the world for seven years. Her performance in recent competitions was disappointing, but during training she unofficially beat her official world record time. So she can be expected to set a new world record in the 100-meter backstroke during the upcoming world competition. Which one of the following, if true, most strengthens the argument?
A: Peterson has also set world records in several other swimming events.
B: Peterson had the flu during a recent competition.
C: Peterson has in each of the past seven years swum faster during world competitions than during training for those competitions.
D: Peterson is widely expected to win the 100-meter backstroke in the next world competition.
Choose A, B, C or D as your solution.
C