2024 AMC 12A Problem 9

Let M be the greatest integer such that both M + 1213 and M + 3773 are perfect squares. What is the units digit of M?

\textbf{(A) }1 \qquad \textbf{(B) }2 \qquad \textbf{(C) }3 \qquad \textbf{(D) }6 \qquad \textbf{(E) }8 \qquad

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.