What Factor Do Scientists Think Is Causing Some of Antarctica's

What factor do scientists think is causing some of Antarctica's outlet glaciers to flow into the ocean faster?

A) The temperature of the ice is increasing, allowing it to deform and flow faster.
B) As ice shelves break apart, their buttressing effects are removed.
C) The glaciers are being lubricated by liquid water from moulins.
D) Decreased snowfall is speeding up the rate of glacier flow.