Final answer:
An observer cannot see Polaris in the night sky at the South Pole or in places within 23° of the South Pole, south of the Antarctic Circle.
Step-by-step explanation:
An observer cannot see Polaris in the night sky at any time during the year if they are located at the South Pole or in places within 23° of the South Pole, south of the Antarctic Circle.
This is because on June 21, all places within 23° of the South Pole do not see the Sun at all for 24 hours, resulting in constant darkness.
Therefore, an observer at these locations would not be able to see Polaris, which is near the northern celestial pole.