The correct answer is B. Pushyamitra Shunga.
Pushyamitra Shunga was the founder of the Shunga dynasty, which ruled over the Indian subcontinent from 185 to 73 BCE. He was a general in the Mauryan army who assassinated the last Mauryan emperor, Brihadratha, and seized the throne. Pushyamitra was a powerful and successful ruler who expanded the Shunga empire to include much of the Indian subcontinent. He was also a patron of the arts and literature.
A. Brihadratha was the last Mauryan emperor. He was assassinated by Pushyamitra Shunga in 185 BCE.
B. Pushyamitra Shunga was the founder of the Shunga dynasty. He ruled from 185 to 149 BCE.
C. Vasumitra was the third Shunga emperor. He ruled from 149 to 141 BCE.
D. Agnimitra was the fourth Shunga emperor. He ruled from 141 to 130 BCE.