This is a complete sentence.
Answer:
The answer is C. I believe...
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
It is still highly relevant because many racists still believe that mixing races is wrong and that having babies from two different raced parents should not happen.
