The potential difference between the base and the collector Vcb in a PNP transistor in saturation region is -0.5V.

Explanation:
When a PNP transistor is in the saturation region, both the base-emitter junction and the base-collector junction are forward biased. In this region, the transistor operates as a closed switch, allowing a significant amount of current to flow through the collector and emitter terminals.

To understand why the potential difference between the base and the collector Vcb is -0.5V in the saturation region, let's break down the behavior of the PNP transistor in this region:

1. Base-Collector Junction:
- The base-collector junction is forward biased in the saturation region.
- The collector terminal is at a higher potential than the base terminal.
- Due to this forward bias, the collector current (Ic) flows from the collector to the base region.

2. Base-Emitter Junction:
- The base-emitter junction is also forward biased in the saturation region.
- The emitter terminal is at a higher potential than the base terminal.
- Due to this forward bias, the base current (Ib) flows from the base to the emitter region.

3. Potential Difference Vcb:
- The potential difference Vcb is the difference in potential between the base and collector terminals.
- Since the collector terminal is at a higher potential than the base terminal, Vcb is negative.
- The magnitude of Vcb depends on the biasing conditions and the characteristics of the transistor.
- In the saturation region, the typical value of Vcb for a PNP transistor is -0.5V.

Therefore, the correct answer is option 'B' (-0.5V) as the potential difference between the base and the collector Vcb in a PNP transistor in the saturation region is -0.5V.