Question 1624Navigation General

The correct answer is B) principal vertical. The principal vertical is the great circle on the celestial sphere that passes through the zenith (the point directly overhead) and the north and south celestial poles. This is the correct answer because the question specifically describes a great circle passing through the zenith and the north and south poles, which is the definition of the principal vertical. The other answer choices are incorrect because: A) the ecliptic is the great circle representing the apparent path of the sun on the celestial sphere, C) the hour circle is a great circle passing through the celestial poles, and D) the prime vertical is the great circle passing through the east and west points on the horizon.