The group that would have been least likely to participate in the Indian Rebellion of 1857 against the British is Hindu sepoys hired by the British East India Company.
While some sepoys did indeed join the rebellion, many others remained loyal to the British, as they were employed by the British East India Company and relied on their jobs for livelihood. The other groups listed—peasants, Sikhs, and Marathas—had various grievances against British policies and were more likely to involve themselves in the uprising.