Answer:
option b
1.5
Explanation:
Given in the question an equation,
 y = 1.5sin4x
The amplitude of y=asin(x) represents half the distance between the maximum and minimum values of the function.
Amplitude = |a|
In the equation  y = 1.5sin4x, a = 1.5 
So, amplitude of graph  y = 1.5sin4x = 1.5