A. Hazrat Abu Bakar Siddique (R.A)
B. Hazrat Umar Farooq (R.A)
C. Hazrat Usman Ghani (R.A)
D. Hazrat Ali (R.A)
The correct answer to the question: "Which Khulifa-e-Rashid announced the war against the people who were unwilling to pay zakat?" is "Hazrat Abu Bakar Siddique (R.A)".