If the functions W, X, Y and Z are as follows
$$\eqalign{ & {\text{W}} = {\text{R}} + \overline {\text{P}} {\text{Q}} + \overline {\text{R}} {\text{S}} \cr & {\text{X}} = {\text{PQ}}\overline {\text{R}} \overline {\text{S}} + \overline {\text{P}} \overline {\text{Q}} \overline {\text{R}} \overline {\text{S}} + {\text{P}}\overline {\text{Q}} \overline {\text{R}} \overline {\text{S}} \cr & {\text{Y}} = {\text{RS}} + \overline {{\text{PR}} + {\text{P}}\overline {\text{Q}} + \overline {\text{P}} \overline {\text{Q}} } \cr & {\text{Z}} = {\text{R}} + {\text{S}} + \overline {{\text{PQ}} + \overline {\text{P}} \overline {\text{Q}} \overline {\text{R}} + {\text{P}}\overline {\text{Q}} \overline {\text{S}} } \cr} $$
Then (a) W Z,X Z = = (b) W Z,X Y = = (c) W = Z, X = Y (d) W Y Z

A. $${\text{W}} = {\text{Z, X}} = \overline {\text{Z}} $$

B. $${\text{W}} = \overline {\text{Z}} {\text{, X}} = {\text{Y}}$$

C. $${\text{W}} = {\text{Z, X}} = {\text{Y}}$$

D. $${\text{W}} = {\text{Y}} = \overline {\text{Z}} $$

Answer: Option A