The correct sentence is C. I have a lot of money.
Choice A should have been He has a lot of money.
Choice B should have been You have a lot of money.
HAS is used with the 3rd person singular.
HAVE is used with the 1st and 2nd person singular and plural, and 3rd person plural.
Choice A is 3rd person singular.
Choice B is 2nd person singular
Choice C is 1st person singular.