Correct answer: A. It drew a boundary linked with displacement of millions
Explanation: The Radcliffe Line is linked with the tragedy of Partition because it marked the new boundary between India and Pakistan in 1947. The boundary divided areas of Punjab and Bengal and separated many communities, homes, farms, places of work, and family networks. Since the line was announced around the time of independence, millions of people crossed the new border in search of safety or to join the country they were assigned to. This movement involved violence, fear, loss of property, and separation from familiar places.
The question asks why the line is remembered as part of a human tragedy, not merely what it was technically. Option A correctly connects it with the displacement of millions. The other choices refer to unrelated events: the salt law belongs to colonial taxation and protest, Congress was founded through a different historical process, and the Swadeshi Movement arose in another context. Therefore, the humanitarian consequences of the Partition boundary make A the correct choice.