The Primary Difference Between Valley Glaciers and Continental Ice Sheets

The primary difference between valley glaciers and continental ice sheets is that

A) the ice sheets do not flow
B) the valley glaciers form at high altitudes while the ice sheets form at high latitudes
C) the valley glaciers form in warm periods as well as cold periods
D) the ice sheets initially develop at the poles and valley glaciers can develop in any mountain chain
E) ice sheets are larger than valley glaciers