Frequency deviation calculation from FM equation

Calculate the maximum frequency deviation for the FM signal
v(t)= 10 cos(6000t+ 5sin2200t)

a) 2200 Hz
b) 6000Hz
c) 1750Hz
d) 11000Hz

Correct Answer: c) 1750Hz

Explanation:

A standard FM signal is represented by
v(t)= A_c cos(2πf_ct+ k_fsin2πf_mt)
A_c = carrier amplitude
f_c= carrier frequency
k_f= modulation index
f_m = modulating frequency = 2200/2π = 350 Hz
k_f = frequency deviation/modulating frequency
5= freq deviation/ 350
Therefore, deviation= 5 *350
= 1750Hz