The temperature of a planet is generally influenced by its distance from the Sun, with closer planets typically experiencing higher temperatures. In the table provided, we can see the orbital radii measured in astronomical units (AU):
- W: 5.2 AU
- X: 0.72 AU
- Y: 1.0 AU
- Z: 19.1 AU
Among these, Planet X, with an orbital radius of 0.72 AU, is the closest to the Sun. Therefore, it is likely to experience the highest temperature.
So, the answer is X.