The correct answer is (a) Man Sehra.
The Man Sehra inscription is a rock inscription found in the Man Sehra village in the Indian state of Rajasthan. It is dated to the 3rd century BCE and is written in the Brahmi script. The inscription records the construction of a dam by a king named Rudradaman. The inscription also mentions the Aryans and their movement from Iran to India.
The other options are incorrect.
(b) Slialibajgarhi is a Buddhist stupa located in the Indian state of Madhya Pradesh. It is dated to the 2nd century BCE. The stupa does not contain any inscriptions.
(c) Boghajkoi is a Buddhist monastery located in the Indian state of Maharashtra. It is dated to the 1st century BCE. The monastery does not contain any inscriptions.
(d) Junagarh is a city in the Indian state of Gujarat. It is home to a number of historical monuments, including the Junagarh Fort. The fort does not contain any inscriptions that mention the Aryans.