SAT Question 5f07b257: Nonlinear Functions answer and explanation with Desmos solution

The y-intercept of the graph of a function in the xy-plane is the point where the graph intersects the y-axis. The graph of the polynomial function shown intersects the y-axis at the point $(0,4)$. It's given that the y-intercept of the graph is $(0,y)$. Therefore, the value of $y$ is $4$.