Perfect Squares And Units Digit
Let $M$ be the greatest integer such that both $M+1213$ and $M+3773$
are perfect squares. What is the units digit of $M$?
\[
\textbf{(A)}\ 1 \qquad
\textbf{(B)}\ 2 \qquad
\textbf{(C)}\ 3 \qquad
\textbf{(D)}\ 6 \qquad
\textbf{(E)}\ 8
\]