(a) False; Historians rely on coins, inscriptions, architecture and textual records for information for the study of period from 700 to 1750.
(b) True
(c) True
(d) False; Sultan Ghiyasuddin Balban (1266-1287) ruled a vast empire that stretched from Bengal (Gauda) in the east to Ghazni (Gajjana) in Afghanistan in the west and included all of south India (Dravida).