The border line which separates India and Pakistan is known as ______.

Correct option is C

The correct answer is (c), Radcliffe line.
The Radcliffe Line was the boundary demarcated between the Indian and Pakistani portions of the Punjab Province and Bengal Presidency of British India. It was named after Cyril Radcliffe, who, as the joint chairman of the two boundary commissions for the two provinces, had the ultimate responsibility to equitably divide 175,000 square miles (450,000 km2) of territory with 88 million people.
The Radcliffe Award The demarcation line was published on 17 August 1947 upon the Partition of British India. Today, its western side of the line is part of the India–Pakistan border while its eastern side serves as the Bangladesh–India border.
The Radcliffe Line is one of the most controversial borders in the world.