The correct answer is option 'C', Meridians of longitude.

Explanation:
Meridians of longitude are the lines of reference that run from the North Pole to the South Pole on the Earth's surface. These lines are used to measure the east-west position of a location on the Earth's surface.

Meridians of Longitude:
- Meridians of longitude are imaginary lines that encircle the Earth from the North Pole to the South Pole.
- They are also known as lines of longitude or meridians.
- The prime meridian, which passes through Greenwich, London, is considered the starting point for measuring longitude and is assigned a value of 0 degrees.
- The meridians of longitude are numbered from 0 degrees to 180 degrees, both east and west of the prime meridian.
- The 180-degree meridian, also known as the International Date Line, is opposite the prime meridian and serves as the dividing line between one calendar day and the next.

Uses of Meridians of Longitude:
- Determining Time Zones: The meridians of longitude are used to define time zones around the world. Each time zone is approximately 15 degrees wide and is centered on a meridian of longitude.
- Navigation: Sailors and pilots use meridians of longitude to navigate across the globe. By knowing their current longitude and the desired longitude, they can determine the direction and distance they need to travel.
- Geographic Coordinates: The combination of latitude and longitude coordinates provides a unique identifier for any location on the Earth's surface. This is useful for mapping, surveying, and locating specific places.

Conclusion:
In summary, the lines of reference running from the North Pole to the South Pole are called meridians of longitude. They are used to measure the east-west position of a location on the Earth's surface and have various applications in navigation, time zones, and geographic coordinates.