You didn't underline anything, so we cannot know for sure what the correct answer is. However, I'll just write down the entire infinitive phrases in these sentences, and you can see the answer based on that:
1. to see a great play
2. to cheer good plays
3. to practice until you know all the plays
A is wrong cause summer is capitalized
B is wrong cause Florida isn’t capitalized
C should be correct cause the week day is capitalized, and the movie is too but the period should be a “,”.
D is wrong cause birthday shouldn’t be capitalized
Answer:
cccccccccccccccccccccccccccoooooooooooooooootttttttttttttttteeeeeeeeeeeeeeeeeeee
Explanation: