Answer: chloropentane
Step-by-step explanation:
When a hydrocarbon has a halogen atom, its properties will change because this group has a higher molecular weight and a higher polar moment that will be hard to defeat in order to reach the boiling point.
The Boiling point of the pentene is 30°C // pentane is 36,1°C // 2-pentanone is 101°C and chloropentane 108°C.
Simple hydrocarbons have lower boiling points compare with those with a functional group like the Oxygen in the 2-pentanone and the Chlorine in the chloropentane. On the other heand, Oxygen is not as electronegative and heavy like Chlorine, thus the chloropentane is the one with higher boiling point.