Which of the following serve as examples of strong separation of auties within the context of the acquisition$/$payment process?Selectone:a$.$Establishing a purchasing department$$ b$.$ Requiring all purchases over $$500$ to be approved by a manager.Neither establishing a purchasing department nor requiring all purchases over $$500$ to be approved by a managerd. Both establishing a purchasing department and requiring all A purchases over $$500$ to be approved by a manager