Question

at which time of day is the heat flow entering earth’s atmosphere (hₙ) highest?
sunrise
midday
sunset
midnight

Explanation:

At midday, the sun is at its highest point in the sky for a given location. This results in the sun's rays hitting the Earth's atmosphere more directly, leading to a higher - intensity and thus higher heat flow entering the atmosphere compared to sunrise, sunset, or midnight.

Answer:

B. midday