Which of the following are components of an amino acid?

Amino acids are the building blocks of proteins and contain a specific structure that includes three essential components: an amino group (NH2), a carboxyl group (COOH), and a unique side chain known as the R group.

The amino group consists of a nitrogen atom and two hydrogen atoms, giving it the formula NH2. This group is crucial for the basic nature of amino acids. The carboxyl group, COOH, contributes to the acidic property of amino acids, allowing them to act as weak acids in solution. Lastly, the R group varies among different amino acids, providing each one with unique properties and characteristics that influence protein structure and function.

This combination of an amino group, a carboxyl group, and a variable side chain (R group) is what defines all amino acids, making option B the correct choice. The other provided options consist of incorrect combinations of elements and functional groups that do not represent the typical structure of amino acids.