Which of the Following Statements Explains Why Low Clouds Slow

Which of the following statements explains why low clouds slow surface cooling at night better than clear skies do?

A) Clouds start convection currents among them.
B) Water droplets in the clouds reflect infrared energy back to the Earth.
C) Clouds absorb and radiate infrared energy back to the Earth.
D) Clouds conduct heat better than clear night air does.