Let's you and me discuss a few things that you already know:
-- What's a y-intercept ?
The y-intercept on a graph is the place where it crosses the y-axis.
-- That's the value of 'x' at the y-intercept ?
The y-intercept is on the y-axis, so 'x' is zero there.
-- Good !  So how would you find the y-intercept of a function ?
You say that  x=0  and look at what 'y' is.
-- Very nice.  What's the function in this question ?
The function is
              f(x)  [or 'y']  =  x⁴ + 4x³ - 12x² -32x + 64   .
--  Excellent.   What's the value oif that function  (or 'y')  when  x=0  ?     
        It's just  64 .
-- Beautiful.
   Are there any answer choices that cross the y-axis at  64 ?
   How many are there ?
   There's only one.
   It's the upper one on the right hand side.