Starting from the centre of the earth having radius R , the...

Acceleration due to gravity at a depth $d$ below the surface of the earth is given by $$\begin{aligned} g_{\text{depth }} & =g_{\text{surface }}\left(1-\frac{d}{R}\right) \\ & =g_{\text{surface }}\left[\frac{R-d}{R}\right]=d_{\text{surface }}\left(\frac{r}{R}\right) \end{aligned}$$ Also, for a point at height $h$ above surface, $g_{\text{height }}=g_{\text{surface }}\left[\frac{R^2}{(R+h)^2}\right]$ Therefore, we can say that value of $g$ increases from centre to maximum at the surface and then decreases as depicted in graph (b).