A sensitivity of transfer function $$T = \frac{(A_1 + kA_2)}{(A_3 + kA_4)}$$ with respect to parameter k is given by

A

$$\frac{k(A_2A_3 - A_1A_4)}{((A_3 + kA_4)(A_1 + kA_2))}$$

B

$$\frac{(A_2A_3 - A_1A_4)}{((A_3 + kA_4)^2)}$$

C

$$\frac{k(A_2A_3 - A_1A_4)}{((A_3 + kA_4)^2)}$$

D

$$\frac{(A_2A_3 - A_1A_4)}{((A_3 + kA_4)(A_1 + kA_2))}$$