I think this one should be an easier one, but I can't seem to figure it out.

36. If F is a function such that, for all positive integers x and y F(x,1)=x+1, F(1,y)=2y, and F(x+1, y+1) = F( F(x, y+1), y), then F(2,2) =

a) 8

b) 7

c) 6

d) 5

e) 4

correct answer is D.

Thanks for your responses.