Explain how the shading of the direct light of the sun causes a lunar eclipse.

A lunar eclipse occurs when the Moon moves through the Earth's umbra. Earth ever has an umbra, that is produced by the Sun. On those rare moments, while the Moon, Earth and the Sun are wholly fixed up just accurate, the Moon moves through this umbra. This would occur every entire moon if the Moon revolving about the Earth in the corresponding plane as the Earth circles around the Sun.

iii. and iv. only is the right answer

the answer is blue river