Consider the multiplexer based logic circuit shown in the figure.
Which one of the following Boolean functions is realized by the circuit?
- $F= W \overline{S_1} \: \overline{S_2}$
- $F= WS_1+WS_2 + S_{1}S_{2}$
- $F= \overline{W}+S_{1}+S_{2}$
- $F= W\oplus S_{1}\oplus S_{2}$