For whom were the pichhwais painted in Nathdwara?

The correct answer is Option 4: Shrinathji, the deity

The pichhwais were painted on cloth for the deity Shrinathji.

Nathdwara, a town close to Udaipur and a prominent Vaishnava centre, also emerged as a school of painting in the late seventeenth century. Large backdrops called pichhwais were painted on cloth for the deity, Shrinathji, for several festive occasions.