Need help with below future value problem.

Calculating sinking fund payment:

In order to provide for their son's college education, a family decides to open a sinking fund with the objective of having $50000 after 12 years. If payments are made monthly into an account paying 8% compounded monthly,

(A) How much must each payment be?

(B) What is the amount of interest accumulated during the last year?

(C) If after 12 years, the son decides not to go to college, and no deposit or withdrawal is made for 10 years while the account is generating interest at the same rate, how much is in the account after these 10 yrs?