Determine the Period and Amplitude of the Following Function $y=4 \cos \left(\frac{3 x}{4}+\frac{\pi}{4}\right)$

Multiple Choice

Determine the period and amplitude of the following function.
$y=4 \cos \left(\frac{3 x}{4}+\frac{\pi}{4}\right)$

A) period: $2 \pi$ , amplitude: 2
B) period: $10 \pi$ , amplitude : 2
C) period: $5 \pi$ , amplitude : 4
D) period: $\frac { 8 \pi } { 3 }$ ; amplitude : 4
E) period: $3 \pi$ , amplitude : 4