【单选题】

Earthshine--the faint light that allows us to see the dark side of the moon when the moon is a thin crescent--is sunlight reflected from the earth to the moon, then back again.Earthshine is variable because the earth’s reflectivity changes as large cloud masses come and go. The moon with its earthshine acts as a crude weather satellite by reporting, in a very simple way, the general state of terrestrial cloudiness.Because the amount of light reflected from the earth depends on the amount of cloud cover, the brightness of the dark side of the moon varies.

As the phase of the moon progresses beyond a thin crescent, earthshine fades in a day or two. This is because the amount of sunlit earth available to make earthshine diminishes as the moon orbits the earth.Also, there is the increasing glare of the moon’s growing crescent, which causes a loss of visibility by irradiation.
The word crude in paragraph 1 is closest in meaning toA．false
B．stormy
C．random
D．simple