I do not understand your question. Where is it written that the y-intercept is 4?
The answer to the question is 2 because obviously the line and the parabola intersect at one point whose y-coordinate is 2.
You need to know the difference between the terms "y-intercept" and "y-coordinate of the intersection" as a student who is taking the SAT - that's why I directed you to watch the videos.
y-intercept and coordinate of intersection are two different things in Algebra. I think you got confused with the terms here.
Please watch the first five minutes of the linear equations video where I explain what the y-intercept it.
To understand what the intersection is, you can watch the second video on linear equations where I explain what a system of equations is.