When can an eclipse occur?

An eclipse occurs when the Sun, Moon, and Earth align in a specific way. In the case of a solar eclipse, the Moon passes between the Earth and the Sun, blocking the Sun's light either partially or completely from reaching the Earth. For a lunar eclipse, the Earth comes between the Sun and the Moon, casting a shadow on the Moon. This alignment is crucial; it is not just the presence of the Earth and Moon but their specific arrangement with the Sun that results in an eclipse.

While the alignment of the Earth and Moon alone might suggest some interaction, it is the presence of the Sun in the configuration that leads to the eclipse phenomenon. Other options mention situations that do not guarantee an eclipse, such as simply having a full Moon or the Sun setting, which does not involve the necessary alignment for an eclipse to occur.