Eskers are glacial features formed when sediment is deposited in a broad ramp-like accumulation downstream large amounts of debris are deposited along the sides of a glacial valley streams flowing in tunnels beneath glaciers deposit sand and gravel blocks of stagnant ice become buried in drift and eventually melt

For the options given below i would say it is answer C: Streams flowing in tunnels beneath glaciers deposit sand and gravel

streams flowing in tunnels beneath glaciers deposit sand and gravel

Explanation:

Eskers are the glacial features formed when the glaciers melt. The melted ice forms a channel and tunnel in the glacier. These tunnels takes away the debris like gravel and sand along with them. Over the time this debris get compacted and solidifies forming a ridge like feature called as eskers.  

According the above explanation streams flowing in tunnels beneath glaciers deposit sand and gravel