When viewed from Earth, Mars appears to change colors. This most likely happens because

A. gases in the dense Martian atmosphere are constantly changing.

B. volcanic activity produces thick gas clouds.

C. dust storms lasting for weeks cause the atmosphere to change color.

D. active volcanoes on the Mars surface intermittently flood the surface with lava.

This is because dust storms lasting for weeks cause the atmosphere to change color.

Explanation:

Dust is a major component in the mars atmosphere . A dust storm that lasts long period will effect the visibility , atmospheric structure of the mars .  There are two types of storms that are found on mars , one of them is covered large areas and last for more than six  days in mars . The second one covers smaller areas and stays for short interval of time . Scientists even discovered few storms which last more than 15 to 20  martian days which are responsible for color change.  

d is the answer i came up with

trig 15.3 cos