Suppose P is the set of polynomials with coefficients in Z_5 and degree less than or equal to 7. If the operator D sends p(x) in P to its derivative p′(x), what are the dimensions of the null space n and range r of D?
(A)n = 1 and r = 6 (B)n = 1 and r = 7 (C)n = 2 and r = 5 (D)n = 2 and r = 6
D