\( S = \overline{(A . B)} . \overline{(C + D)} + A . B . C \)

\( S = (\overline{A \cdot B}) \cdot (C + D) + \overline{A \cdot B \cdot C} \)

\( S = (A . B) + (C + D) + A . B . C \)

\( S = \overline{(A, B)}, (C + D) + \overline{A, B, D} \)