The graph between angle of deviation ($\delta$) and angle of incidence ($i$) for a triangular prism is represented by:

For a prism, as the angle of incidence $i$ increases, the deviation $\delta$ first decreases, reaches a minimum (${\delta }_m$), and then increases. The curve is non-linear and U-shaped (specifically, it is steeper at small $i$ than at large $i$). This corresponds to the graph in Option B.