Correct option is B
The Revolt of 1857 started from Meerut. It was the first site of armed rebellion against the British East India Company, marking the beginning of the widespread uprising.
Agra: Was involved in the revolt but not the starting point.
Kanpur: Saw a significant uprising under leaders like Nana Sahib but again, not the initial spark.
Delhi: Became the centre of the revolt shortly after Meerut, with the reclamation of the city under rebel control.