Calculate the derivative for g(z) = (z² - 16) / (z - 3) (z² - 9) / (z - 4) for z = 4 and z = 3.
a) g'(4) = -5/3, g'(3) = 4
b) g'(4) = -4/3, g'(3) = 3
c) g'(4) = -3/2, g'(3) = 5
d) g'(4) = -2/3, g'(3) = 2