AHSME 1979 Problem 5

Find the sum of the digits of the largest even three digit number (in base ten representation) which is not changed when its units and hundreds digits are interchanged. $\textbf{(A) }22 \textbf{(B) }23 \textbf{(C) }24 \textbf{(D) }25 \textbf{(E) }26$