Solve the sum and identify the digit that repeats twice in the box. \[\frac{\begin{align} & \,\,\,\,\,\square ~~5~~\,6 \\ & +\text{ }\square ~\,\square ~\,9 \\ \end{align}}{\,\,\,\,\,6\,\,\,0\,\,\,5}\]

• A. 1         
• B. 0         
• C.      4         
• D.      5