To find the minimal function from the given Karnaugh Map (K-map), let's analyze the grouping of 1s and 'don't care' conditions (X) in the map.
The K-map is a 4-variable map with variables PP, QQ, RR, and SS. The positions of the variables in the K-map are as follows:

- The 1s can be grouped as follows:
- The entire row for RS=00RS=00 can be grouped into one group, yielding S′=0S′=0, so the simplified expression is Q′S′Q′S′.
- The first two columns, covering both 00 and 10 for PQPQ where RS=10RS=10, can be grouped, yielding P′=0P′=0, so the simplified expression is P′S′P′S′.
Therefore, the minimal function generated by this K-map is Q'S' + P'S'.
Hence, the correct answer is: Q'S' + P'S'.