The correct answer is “Chandra”.
The iron pillar in the courtyard of the Quwwatul Islam Mosque of Delhi is believed to have been erected in memory of Chandra.
Chandra Gupta II, also known as Vikramaditya, was a powerful emperor of the Gupta Empire who ruled from 375 to 415 CE. The pillar's exceptional resistance to rust suggests advanced metallurgical skills, potentially aligning with the Gupta era's technological advancements.