The earliest description at Bakhtiyar Khilji’s invasion of Bihar is in

Tarikh-i-Hind
Tabaqat-i-Nasiri
Taj-ul-Maasir
Tarikh-i-Mubarak Sahi

The earliest description of Bakhtiyar Khilji’s invasion of Bihar is in Tarikh-i-Hind, written by Minhaj-i-Siraj. Minhaj-i-Siraj was a 13th-century historian who served as the wazir (chief minister) of the Delhi Sultanate under Iltutmish. Tarikh-i-Hind is a chronicle of the history of India from the time of the Mahabharata to the reign of Iltutmish. The book is divided into three parts: the first part deals with the history of India before the Muslim conquest, the second part deals with the history of the Delhi Sultanate, and the third part deals with the history of the reign of Iltutmish.

Minhaj-i-Siraj’s account of Bakhtiyar Khilji’s invasion of Bihar is one of the most detailed and reliable accounts of the event. Minhaj-i-Siraj was an eyewitness to the invasion and he provides a vivid description of the events. He also provides a detailed account of the military and political situation in Bihar at the time of the invasion.

Minhaj-i-Siraj’s account of Bakhtiyar Khilji’s invasion of Bihar is an important source of information about the event. It is a valuable source for historians who are studying the history of India and the history of the Delhi Sultanate.

The other options are not as reliable as Tarikh-i-Hind. Tabaqat-i-Nasiri is a chronicle of the history of the Delhi Sultanate written by Minhaj-i-Siraj’s son, Hasan Nizami. Taj-ul-Maasir is a chronicle of the history of the Delhi Sultanate written by Ziauddin Barani. Tarikh-i-Mubarak Sahi is a chronicle of the history of the Delhi Sultanate written by Amir Khusrow. These books are all valuable sources of information about the history of the Delhi Sultanate, but they are not as reliable as Tarikh-i-Hind when it comes to the events of Bakhtiyar Khilji’s invasion of Bihar.