Olefins are

A. Saturated hydrocarbons

B. Unsaturated cyclic compounds (hydrocarbons)

C. Present in substantially good quantity in crude petroleum

D. None of these

Answer: Option B

Solution(By Examveda Team)

In petroleum refinery engineering, olefins are unsaturated cyclic compounds (hydrocarbons) (Option B).

Olefins, also known as alkenes, are a class of hydrocarbons containing at least one carbon-carbon double bond. They are unsaturated compounds because they contain fewer hydrogen atoms than the corresponding saturated hydrocarbons. Olefins are widely used in the petrochemical industry as feedstocks for producing various chemicals, including plastics, solvents, and synthetic fibers.

Therefore, the correct option is Option B: Unsaturated cyclic compounds (hydrocarbons).