Want the option to keep studying online: Girls 10 Boys 3 Row Total 13

Don't want the option to keep studying online: Girls 5 Boys 7 Row Total 12
Column Total: Girls 15 Boys 10 Row Total 25

Which mathematical sentence can be used to calculate the probability of selecting a student who wants the option to keep studying online or is a boy?

A. 13/ 25 + 10/25
B. 13/25 * 10/25
C. 13/25 + 10/25 - 3/25
D. 3/25