What Happens to Wave Energy and Erosion When Riprap or Seawalls

Multiple Choice

What happens to wave energy and erosion when riprap or seawalls are installed?

A) Wave height rises against the wall, and erosion concentrates at the base of the wall.
B) Waves that strike the riprap are reflected back against the incoming waves to cancel them.
C) Waves move up and down against steep surfaces in deep water, so they don't do anything.
D) Waves lose their energy against riprap or seawalls, so they permanently protect the coast.
E) Waves pulverize the riprap and seawalls, creating sand that helps maintain the beach.