Q 52 : ans is A.
first we can easly find.
follow of A = {a,b}, all symbols appeared after A in RHS
follow of B = {a,b,\$}, as B is at the end in RHS, follow(B) = follow (S) and S is also at the end in RHS so follow(S) = follow(A) = {a,b} and S is start symbol, so its follow contains \$ also.
hence, follow(B) = {a,b,\$}
Q 53.
ans is C.