The correct option is D Trade
Bimbisara was the first important king of the Magadha kingdom. He was an ambitious ruler. Apart from war, he adopted other strategies to expand his empire. He established matrimonial alliances with the high-status Lichchavi clan of Vaishali and the ruling family of Kosala. Bimbisara also conquered Anga—the modern-day West Bengal and gained access to the Ganges delta region.