The correct answer is: A. the parallels of longitude.
The Earth rotates on its axis once every 24 hours. This means that the Sun appears to move across the sky from east to west. The time at a place is determined by the position of the Sun in the sky. The Sun is directly overhead at noon at the equator. As you move north or south of the equator, the Sun appears lower in the sky at noon. The time difference between two places is equal to the difference in their longitude. Longitude is measured in degrees, with 180 degrees of longitude from the Prime Meridian to the International Date Line.
The parallels of latitude are circles that run east and west around the Earth. They are not used to determine the time at a place. The distance from the equator does not affect the time at a place. The distance from the Prime Meridian does not affect the time at a place.