Which party used political machines to attract immigrant voters

Which act of the conquistador pizarro was crucial in overthrowing the inca? a. the destruction of the ancient inca city, machu picchu b. the siege of the inca capital near the cuzco valley c. the execution of the last inca ruler, atahualpa d. the unexpected deaths of 3 million inca warriors e. the murder of former inca emperor, huascar