The change in the visibility of constellations at midnight from April to October in New York is due to the Earth's **revolution **around the Sun. This revolution changes the section of the celestial sphere that is visible at midnight. Therefore, different constellations are seen during these two periods. ;
Some constellations are visible at midnight in April but not in October because the Earth revolves around the Sun. This revolution changes which constellations are visible, depending on the time of year. Therefore, the correct answer is option (c).
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