I hate math assignments and it's due tomorrow and the teacher is stupid and won;t help people. I was away when it was explained so i have no idea what to do!!

Suppose an NBA player makes 90% of his free throws. This player takes 20 free throws in the course of a game.

Find the probabilits of his making:

A) Atleast 19 of the 20 free throws.

B) Less than 15 of the 20 free throws

C) Exactly 90% od the 20 free throws.