The answer is B. When things don't turn out as expected, it can be a welcome surprise.
Explanation:
The statement that best explains the complex theme of the passage is "when things don't turn out as expected, it can be a welcome surprise.". In the passage, Desiree is sure she will win the competition, but another girl ends up winning instead, using a similar project. Instead of being upset and beating herself up about it, Desiree finds a kindred spirit and a lifelong friend.
