Which of the following statements about solar radiation is true?

A. Earth's landmasses and oceans emit radiation back to the atmosphere in the form of longwave radiation.
B. The Earth only emits longwave radiation during daylight hours.
C. The greenhouse effect is crucial to maintaining Earth's surface temperature.
D. Of the solar radiation that reaches the top of Earth's atmosphere, only 41 percent makes it to Earth's surface.
E. The sun gives off primarily longwave radiation.