For three events A, B and C, P(Exactly one of A or B 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) = 1/6.

Then the probability that at least one of the events occurs, is :

(1) 7/32

(2) 7/16

(3) 7/64

(4) 3/16