What geoligic feature might form at the surface of plate A​

Volcanoes will form at the surface of plate A. As the leading edge of plate B subducted and move towards the mantle, it will melt and turns into magma which rise up on the surface of plate A creating volcano.

answer:

Deep ocean trenches, volcanoes, island arcs, submarine mountain ranges, and fault lines are examples of features that can form along plate tectonic boundaries.