http://www.allaboutcircuits.com/vol_4/chpt_9/7.html

I am not sure if I did not see something correctly, but I believe the truth table for this section is incorrect. The logic equation for a 2-to-1 MUX is:

\(D=XA' + YA\)

Therefore, the truth table should be constructed as:

Y X A D
0 0 0 0
0 0 1 0
0 1 0 1
0 1 1 0
1 0 0 0
1 0 1 1
1 1 0 1
1 1 1 1

I apologize in advance if I am incorrect, but this was referenced directly out of my Fundamentals of Logic Design textbook.

 

You are right. It should be corrected. The I0 and I1 columns should be interchanged.