Under whose reign did the Gupta empire reach its greatest size?

A. Chandragupta Maurya

B. Chandra Gupta I

C. Samudra Gupta

D. Chandra Gupta II

The correct answer is option C, the Gupta empire, today India, reached its greatest size under the reign Samudra Gupta.

The inscriptions in the Allahabad Pillar, one of the columns known as of Ashoka which are a series of pillars spread throughout the Indian subcontinent, credit Samudragupta, son of the Licchavi princess Kumaradevi and the Gupta emperor Chandragupta, with extensive military conquests, suggesting that he defeated several kings of northern India, and annexed their territories to his empire, which contributed to this empire's notable expansion.

the correct answer is D. Chandra Gupta II