It had rained all afternoon, but the fans were still ___that their favorite game would still be played.

Correct Answer: C. Optimistic

The correct answer is “Optimistic.” In this sentence, despite the adverse weather conditions (rain all afternoon), the fans maintain hope or positivity that their favorite game will still be played. Therefore, the appropriate word to fill in the blank is “Optimistic,” which means having a hopeful outlook or expecting a favorable outcome.