Explanation

Option A is correct: On 21st June (Summer Solstice) in the Northern Hemisphere, the Earth’s northern axis is tilted at its maximum angle (23.5 degrees) toward the Sun:

– The Sun shines vertically overhead at solar noon along the Tropic of Cancer (23.5° N).
– North of the Arctic Circle (66.5° N), the entire polar region remains illuminated throughout Earth’s 24-hour diurnal rotation, meaning the Sun does not set below the horizon (the phenomenon of the Midnight Sun).
– Option B is incorrect: At the Antarctic Circle, the sun does not rise above the horizon on 21st June (polar night).
– Option C is incorrect: The Sun shines vertically overhead at the Equator during the equinoxes (March 21 and September 23).
– Option D is incorrect: The Sun shines overhead at the Tropic of Capricorn on December 22 (Winter Solstice).

Hence, the correct answer is Option A.