Which of the following must hold good for the expansion of the binomial x^{4} + 1/x^{3})^{15} ?

(A) There exist a term which is independent of x.

(B) 8 ^{th }and 9 ^{th} terms of the expansion have the greatest binomial coefficient

(C) Coefficients of x ^{32} and x ^{-17} are equal

(D) If x = √2 , then number of rational terms in the expansion is 5