The correct option is A Ribonucleic acid
The given structure shows a few nucleotides bonded together to form a long chain, which indicates that the molecule is a nucleic acid and not an individual nucleotide. The sugar molecule in the given structure is ribose, and hence, the molecule has to be ribonucleic acid. Moreover, there is a molecule of uracil shown as part of this polymer, which too, gives a hint that it is RNA and not DNA.