Answer: c) amino acid
Explanation: A nucleotide is primarily composed of three components: a sugar molecule, a phosphate group, and a nitrogenous base. The sugar can be either ribose (in RNA) or deoxyribose (in DNA). The phosphate group is attached to the sugar, and the nitrogenous base can be adenine, guanine, cytosine, thymine (in DNA), or uracil (in RNA). Amino acids, on the other hand, are the building blocks of proteins and do not form part of the nucleotide structure. Therefore, the correct answer is amino acid, as it does not belong to the nucleotide components.