Kinetic energy is directly related to temperature: the higher the temperature, the greater the kinetic energy of the particles in a substance.
In the table provided:
- Sample 1: 98.2 °C
- Sample 2: 46.0 °C
- Sample 3: 100.6 °C
- Sample 4: 31.4 °C
Among these, Sample 4 has the lowest temperature at 31.4 °C. Therefore, Sample 4 has the lowest kinetic energy.
So the correct response is: 4