Step 1 :Let's denote the number of adult tickets as A and the number of children tickets as C.
Step 2 :The first equation represents the total income from the tickets sold: \(23A + 15C = 3103\).
Step 3 :The second equation represents the total number of tickets sold: \(A + C = 138\).
Step 4 :Therefore, the correct matrix representation of the system is: \[\left[\begin{array}{rr|r}23 & 15 & 3103 \\ 1 & 1 & 138\end{array}\right]\]
Step 5 :So, the correct answer is \(\boxed{C}\).