A lunar eclipse occurs when which of the following happens?

• A. The Moon and Sun align but the Moon is not in Earth's shadow.
• B. The Sun blocks the Moon from Earth.
• C. The Moon blocks sunlight from reaching the Earth.
• D. The Earth blocks sunlight from reaching the Moon.

Answer: (D)

During a lunar eclipse, the Sun, Earth, and Moon line up so that the Earth sits between the Sun and the Moon. This blocks sunlight from reaching the Moon and causes the Moon to move into Earth's shadow, often giving it a dim red tint as sunlight passes through Earth's atmosphere and is bent toward the Moon. This is different from a solar eclipse, which happens when the Moon moves between the Sun and the Earth and blocks sunlight from reaching Earth. The situations described where the Sun is between the Earth and Moon or where the Moon blocks sunlight from reaching the Earth describe solar eclipse scenarios, not a lunar eclipse. So the correct idea is that the Earth blocks sunlight from reaching the Moon.