Stratified drift consists mostly of large boulders sand and gravel medium-sized rocks arêtes and horns

The correct answer is sand and gravel.

Explanation:

The stratified drift is an outcome of the glacial melting and movement, that is, primarily at the time of the months of summer. It comprises sorted and stratified debris, in the form of sand and finely grained rocks or gravel, which have been dropped in the glacier front by the little streams of melting water. The stratified drift is generally cleaved by the little streams of the melting water from the glaciers, during the warmest time of the year.