Chapter 8 - Graphing Quadratic Functions - 8.2 - Graphing f(x) = ax^2 + c - Exercises - Page 430: 36

Point $A$

The graph of $f$ is a vertical translation of the graph of $y=ax^2$, where $a>0$. Because the graph of $f$ is above the $x$-axis, it means that $c>0$. When $c$ increases, the graph goes vertically more up and therefore the vertex will be closer to the point $A$ and further than $B$.