Which graph represent the function f(x)=4x^2

The graph of the function  is a transformation of the graph of the parent function ; more precisely, the graph of the function  is the graph of the function  compressed by a factor of 4 in the direction.

Remember that we can compress or stretch the graph of a function in the  direction by multiplying  by a constant .
if , we are compressing  the graph in the direction.
if , we are stretching the graph in the  direction.

We can conclude that the graph of the function  is the graph in the first picture. Also, in the second picture you will see the graph of both the function and its parent function simultaneously.