Detailed Solution:
The correct answer is “S and R both are correct and R, explains S”.
The international date line, established in 1884, passes through the mid-Pacific Ocean and roughly follows a 180 degrees longitude north-south line on the Earth. It is located halfway around the world from the prime meridian — the 0 degrees longitude line in Greenwich, England.
Therefore, both the statement and reason are correct, and the reason effectively explains the statement.