He quotient of 10 and f increased by 2

The "quotient" of two numbers means you have to divide them.  So, the quotient of 10 and f is 10/f.  "Increased by" means plus, so you must add 2 to 10/f.  The equation you get is (10/f)+2.  (Note: you put this in parentheses so that people know to divide 10 and f first.)

(10/f)+2

Well, I think the best answer will be C. Hope That Helps!