The answer is A i hope this helps
ADVERB, hope I could help!
Yes, I think so. Fluent means he knows the language by heart whether that is his first language or not. However, he still could forget some things. Here in the U.S. We still look stuff up all the time in dictionary's or on our phones even though we are fluent in the language. So getting a French dictionary will help more.
Choose which word in the brackets best fits the sentence/sounds better for example for the first one, what would be better: everybody MAKE mistakes or everybody MAKES mistakes?