PAST into a distinct block of times to facilitate the effective study of history. The Periodisation like 'Hindu - Muslim - British' is inappropriate because the religion of the rulers has not been the only important historical change but there were also social, ECONOMIC, and cultural CHANGES.The assigning of the precise date and time spans to historical processes is problematic because economic and social changes KEEP TAKING place, hence precise date and time can't be assigned easily. Hence, the correct answer is (4) A) is wrong, but B) is right.