what do you think may happen to the leading edge of plate a as it continues to move downward why

As per the search results, the leading edge of plate A will melt and turn into magma as it continues to move downward towards the mantle. This is because the mantle is located beneath the crust and is composed of hot, molten rock. The temperature at the bottom of the oceanic crust is high enough to melt the crust, and the leading edge of the plate will eventually melt due to the high temperature.