The of a glacier is where snowfall and moisture collect and compact to ice in the winter, and ice persists throughout the summer.

The answer is - accumulation zone.
The accumulation zone on the glacier is the area that lies above the firn line. It is here where snow accumulates and exceeds the losses form ablation (evaporation, melting and sublimation). The annual glacier equilibrium line separates the accumulation and ablation zone annually.

Answer (d) the greenhouse effect is primarily caused by car and trucks;