Answer:
lubricating oil
Step-by-step explanation:
Of the given fractions, lubricating oil has the highest boiling point of all.
It is a petroleum fraction used for lubrication and reducing friction between moving parts of machineries . 
- Lubricating oil is a heavier fraction of oil. 
- Heavier fractions of oil usually have higher boiling points. 
- Natural gas and gasoline are lighter fractions. 
- They are the first set of fractions to come out in distillation column.