Linearize the following equation around the operating point defined by $u_0=7$ obtaining in each case the transfer function $\frac{Y(s)}{U(s)}$:

$12*y^{\text{'}}+11*u*y=9*u^4+29$

a$.\frac{9256,857}{4,000s+348,000}$

b$.\frac{601960,857}{12,000s+77,000}$

c$.\frac{83344,857}{12,000s+77,000}$

d$.\frac{9256,857}{12,000s+77,000}$