Why Are Fall and Spring Temperatures Colder in Deeper Areas

Multiple Choice

Why are fall and spring temperatures colder in deeper areas of lakes than they are in the winter?

A) Air temperatures are colder in the fall and spring.
B) There is a lag in time for the cold water to reach these depths.
C) Aquatic animals are more active in the winter.
D) Lake stratification causes colder water to sink in spring and fall.