Explanations:The question pertains to the historical relationships and political alliances in 18th century Bengal, specifically focusing on the family ties of Mir Jafar, a significant figure during the period of the Bengal Sultanate. Mir Jafar was a prominent military commander and later became the Nawab of Bengal in 1757 after the Battle of Plassey, where he allied with the British East India Company to overthrow the Nawab Sirajuddaulah.
Mir Jafar's son-in-law, Mir Qasim, was another important figure in the political landscape of Bengal. Mir Qasim was initially appointed as the Nawab of Bihar by Mir Jafar, but later became the Nawab of Bengal after Mir Jafar. Mir Qasim's relationship with Mir Jafar was not only familial but also political, as he was part of the same power structure and often acted in concert with Mir Jafar's interests.
Understanding these relationships is crucial for comprehending the complex power dynamics and political maneuvering that characterized the period. Mir Jafar and Mir Qasim were both involved in the intricate web of alliances and conflicts with the British East India Company, which ultimately led to significant changes in the political landscape of Bengal.
It is important to note that the other options provided in the question are not related to Mir Jafar in the context of his son-in-law. Sirajuddaulah was the Nawab of Bengal before Mir Jafar and was overthrown by him. Chanda Sahib was a prominent figure in the Carnatic region and not related to Mir Jafar. Shah Alam II was the Mughal Emperor and not connected to Mir Jafar through marriage or political alliance.
Thus, the correct answer is Mir Qasim, who was indeed the son-in-law of Mir Jafar and played a significant role in the political history of Bengal during the 18th century.