verb
1.
carry out (something) in gradual stages.
2.
PHYSICS
adjust the phase of (something), especially so as to synchronize it with something else.
noun
1.
a distinct period or stage in a series of events or a process of change or development.
2.
each of the aspects of the moon or a planet, according to the amount of its illumination, especially the new moon, the first quarter, the full moon, and the last quarter.
The answer is C because they all distort the way the earth looks.
