Consider the following statements about water erosion. Identify the right ones. I. Water erosion is significant in the regions of heavy rainfall and steep slopes. II. It takes place mainly in the form of sheet and gully erosion. III. Sheet erosion takes place on level lands after a heavy shower. IV. Gully erosion is common on steep slopes.

• A.  I, II and III only
• B.  II and IV only
• C.  III and IV only
• D.  All