The correct option is B Indo-Gangetic
Indo-Gangetic plains, also called North Indian Plain, are extensive north-central section of the Indian subcontinent, stretching westward from the combined delta of the Brahmaputra River valley and the Ganges River to the Indus River valley. It is named after the Indus and Ganga rivers. It consists of fertile alluvial soil deposited by the rivers and its tributaries.