Kosala Mahajanapada (6th century BCE) is a part of modern day:

Correct option is D

The correct answer is (d) Uttar Pradesh.
 Kosala Mahajanapada was located in the northern region of India, corresponding to the modern-day state of Uttar Pradesh.
 The capital city of Kosala was Ayodhya, an important religious and cultural center in Hinduism.
 Kosala was one of the sixteen Mahajanapadas (great kingdoms) that flourished during the 6th century BCE in ancient India.
 The kingdom included the regions around the cities of Ayodhya, Saketa, and Shravasti.
 During the Buddha's time, the kingdom was ruled by King Prasenajit (Pasenadi), a contemporary of Gautama Buddha.