Who among the following was the founder of the Shunga Dynasty (185 BC - 73 BC)?

Pushyamitra

The correct answer is Option 4- Pushyamitra

Pushyamitra was the founder of the Shunga Dynasty. He was the commander-in-chief of the Mauryan army and assassinated the last Mauryan emperor, Brihadratha, in 185 BC. He then proclaimed himself king and established the Shunga dynasty.

The other options are incorrect because:

Bhagabhadra was the son of Pushyamitra and the second ruler of the Shunga dynasty.
Agnimitra was the third ruler of the Shunga dynasty.
Vasumitra was the fourth ruler of the Shunga dynasty.