A women's health clinic has four doctors and each patient is assigned to one of them. If a patient givs birth btween 8 am and 4 pm, then her chance of being attended by her assigned doctor is 3/4, otherwise it is 1/4. What is the probability that a patient is attended by the assigned doctor when she gives birth?
(A) 25/144
(B) 5/12
(C) 7/12
(D) 1/12