For three events A,B and C, if P (exactly one of B or C occurs) = P(exactly one of B or C occurs) = P (exactly one of C or A occurs; =1/4 and P (all the three events occur simultaneously = 1/16, then the probability that at least one of the events occurs, is
(a) 7/32
(b) 7/16
(c) 7/64
(d) 3/16
