The correct options are
A Fertile Indo-Gangetic plains
C Establishment of sea routes through the Bay of Bengal
Bengal, located in the Indo-Gangetic plains, was one of the most fertile and wealthiest provinces in India. The industries and commerce in the Bengal province were well-developed. The British had established many sea routes through the Bay of Bengal to facilitate the trade of goods. The Governor-General headed the administration of India from the Bengal Province during the British rule in India.