Organic chemistry is currently defined as

a. the study of compounds made only by living cells.

b. the study of carbon compounds.

c. the study of natural (as opposed to synthetic) compounds.

d. the study of hydrocarbons.

B

Explanation:

Organic chemistry is defined as the study of carbon compounds.

Organic compounds were first thought to be compounds that could only be produced by living organisms. This theory was disproved when scientists synthetically made urea from ammonia in a lab.

Organic compounds are now known as compounds where carbon atoms are covalently bonded to other elements. This could be hydrogen or oxygen (in the case of lipids or carbohydrates) or nitrogen (in the case of amino acids).