On 21st June, the Sun
- does not set below the horizon at the Arctic Circle
- does not set below the horizon at Antarctic Circle
- shines vertically overhead at noon on the Equator
- shines vertically overhead at the Tropic of Capricorn
The equator is the circle where the Sun is directly overhead at noon on the equinoxes.
The Arctic and Antarctic Circles are located at ±66.5 degrees latitude. This means that on December 21, when the Sun is directly over the Tropic of Capricorn at noon, it will not be visible from the Arctic Circle. So, above the Arctic Circle, there is a period during the winter when the sun remains below the horizon.
The same is true of the Antarctic Circle during Southern Hemisphere winter. On June 21st, when the Sun is directly over the Tropic of Cancer at noon, it is not visible from below the Antarctic Circle.
The correct option is A.