Verified answer

B. Oxygen

Hydrocarbons can have rings (cyclohexane)

Carbon-carbon and carbon-hydrogen bonds are key formations in hydrocarbons (HYDRO for hydrogen, and CARBONS for carbons.)

The definition of a hydrocarbon is an organic molecule with only carbons and hydrogens.

Therefore, it will have no oxygens (nor any other elements).

QUIZ for you:

Which of the following are not hydrocarbons?:

a) Methane (CH4)

b) Acetic Acid (CH3COOH)

c) Ammonia (NH3)

d) Hexane (C6H14)

e) Carbon dioxide (CO2)

f) Octane (C8H18)

the answer is B.