The correct answer is - A. polar.
The perpetual night appears only on the north pole and the south pole and their closest surrounding areas. This is due to the Earth's inclination which makes it possible for this phenomenon to appear, because of the way the Earth is inclined and positioned towards the Sun throughout the year we have situations when for half of the year one of the poles is not getting any sunlight, while in the other half of the year the other pole is not getting any sunlight. When one of the poles experiences perpetual night, the other experiences a perpetual day.
