Find the derivative of (Asin(kx))/(B2 + x2), where A, k, and B are constants.
Options:
A. (Acos(kx))/(B2 + x2)
B. (Acos(kx))/(B2 - x2)
C. (Acos(kx))/(B2 + 2x)
D. (Acos(kx))/(B2 - 2x)