Answer : Option A
When E=0 , Mux is not enabled. Hence Output =0.
When E=1, Corresponding lines are selected.
Now since counter is a down counter starting at (101). Next sequence will be : (100) , (011) , (010) , (011)....so on
For example , when initially counter is 101: Select lines get S0=1, S1=0. Since S1 is msb. Line 1 is selected.
i.e Output will be I2.
Similarly the sequence will be I2,0,I1,0.