The right option is; C. a cirque
A bowl-shaped depression at the head of a glacial valley is a cirque.
A cirque, (also called corrie) is a bowl shaped basin that has precipitous walls at the head of a glacial valley. Cirque is usually formed by erosion under the bergschrund (series of fissure) of a glacier. The section of a cirque that is cupped shaped is usually steep, while the concave shape is opened on the downhill side. Examples of cirques and their location include; Circo de Gredos in Spain, and Chandra Taal in India.