Correct option (d) Nucleotide
Explanation :
Nucleic acids (DNA and RNA) are linear mixed polymers of nucleotides, so also called polynucleotides. Nucleic acids were first discovered by Miescher (1868-69) as nuclein and named nucleic acid by Altmann (1889). They are formed of C, H, O, N and P comprising nitrogenous heterocyclic bases viz purines orpyrimidines, pentose sugar and phosphoric acid.
