What causes the phases of the moon? A) The amount of sunlight reflected onto the moon from the sun B) The Moon Earth and Sun are lined up in the same place C) It is closer to the Earth at times and further from the earth at other times D) The effect of gravity

A.) The amount of sunlight reflected onto the moon from the sun

Just like the Earth, half of the Moon is lit by the Sun while the other half is in darkness. The phases we see result from the angle the Moon makes with the Sun as viewed from Earth. The lit side does not always face the Earth, as the Moon circles the Earth, the amount of the lit side we see changes.