2. Find the derivative of the following function y(x) = a³ + 3 cos³(x).(A) 3a²-9 cos²(x) sin(x)(B) -9 cos²(x) sin(x)(C) 3a²-9 cos²(x)(D) 9 cos²(x) sin(x)(E) -9 cos²(x) (f) 9 cos²(x)