Why Are Estuaries and Coral Reefs More Productive Than Deeper

Why are estuaries and coral reefs more productive than deeper regions of the ocean?

A) They have more access to light and nutrients.
B) They have more access to light and lower salt concentrations in the water.
C) They have more access to light.
D) They have more access to nutrients and lower salt concentrations in the water.
E) They have lower salt concentrations in the water.