Organic compound invariably contain

Answer: Option A

Organic compound invariably contains Carbon.
Organic compounds are generally chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known.
The organic compound L-isoleucine molecule presents some features typical of organic compounds: carbon-carbon, carbon-hydrogen, as well as covalent bonds from carbon to oxygen and nitrogen.