( a ) european imperialism and american expansionism overseas
I believe, "Tanks were a fast and reliable means of transporting soldiers" is NOT true.
Here are some major changes that was introduced by the British after the revolt of 1857:
The Queen of Great Britain ruled India directly. In the past, it was done by the East India Company.
The Hindu-Muslim unity in the war surprised and made the British afraid. From there, they started the open policy of “Divide and Rule”.
The British left the social practices of Indians alone since interference in cultural and social issues of Indians was one of the reasons why a war took place.