Who established Rai dynasty in Jammu in 50 BC?

Answer: Option A

The Rai dynasty was launched by Adi Rai in the year 3044 of the Kaliyuga era, i.e., 50 BC. He is said to have been contemporary of Vikramaditya of Dharanagari, Ujjain, to whom he professed allegiance. His son Dev Rai succeeded him after 48 years.