To get an output 1 from the circuit shown in the figure, The input must be :
A = 0, B = 1, C = 0
A = 1, B = 0, C = 0
A = 1, B = 0, C = 1
A = 1, B = 1, C = 0
Y = (A+B).C . In order to get Y=1, C needs to be 1 and either or both of A and B needs to be equal to 1. Hence (3) is correct