In Addition to Cutting Laterally, Streams Can Also Cut Downward

In addition to cutting laterally, streams can also cut downward in their channels to form deep valleys and canyons. What best explains how streams can cut downward through solid rock?

A) transported sediment causes abrasion of bedrock.
B) water flowing rapidly over the bedrock causes erosion.
C) acidic water causing chemical weathering of the bedrock.
D) physical weathering of bedrock by freeze and thaw action.
E) occurs in areas where streams encounter weaker layers of bedrock.