Choose the false statement.

choose one:
a. when the rate of ablation equals the rate of accumulation, the glacier retreats.
b. during glacial advance, the toe moves downslope for mountain glaciers and outward for continental glaciers.
c. during glacial advance, the rate of ice accumulation exceeds the rate of ablation.
d. the boundary between the zone of accumulation and the zone of ablation is called the equilibrium line.

(A) When the rate of ablation equals the rate of accumulation, the glacier retreats.

Explanation:

The glacier only retreats when the rate of ablation exceeds the rate of accumulation.

And the reason for the retreats and advancements is because of the regular variations in the shape of Earth's orbit and the configuration its axis sustained result to variations of solar intensity at high latitudes that the glacier retreats during warm summers and advance during cold summers.

And this is called the Milankovitch Cycles