We can see from the diagram that we are comprised of a deoxyribose sugar base and phosphate groups. We can also spot that there are nitrogenous bases present as well, specifically Adenine and Thymine.
Recall that DNA is comprised of a deoxyribose sugar and nitrogen bases Adenine, Thymine, Cytosine, and Guanine.
Since the diagram has both of these present, we can say that this biomolecule is DNA. If this biomolecule is DNA, then it has to be the holder of the blueprints of the cell. Recall also that DNA holds the genetic material of a cell.
Therefore, our best bet is answer choice B.