The correct options are
A Tipu's sons were not well trained in warfare.
B The revolt was unorganized.
C No proper leadership.
The Vellore mutiny failed because of No proper leadership, Tipu's sons were not well trained in warfare and more importantly the revolt was unorganized. The immediate causes of the mutiny revolved mainly around resentment felt towards changes in the sepoy dress code, introduced in November 1805. Hindus were prohibited from wearing religious marks on their foreheads while on duty, and Muslims were required to shave their beards and trim their moustaches.