The sugar molecules of DNA and RNA are both pentose sugars but they differ in the number of oxygen atoms present in them.
Option B
The sugar present in an RNA is called Ribose sugar, from which the name Ribonucleic acid came. This sugar has a formula of C₅H₁₀O₅. This sugar binds with a nitrogen base as well has phosphates group attached on 3' and 5' carbon atoms.
But in DNA the structure is same although the sugar is different. In place of Ribose, the sugar here is deoxyribose from which the name deoxyribonucleic acid came. It's formula is C₅H₁₀O₄. Here, there's no OH group present on the 2' carbon atom of a ribose sugar. This gives more stability to DNA molecule and less probable for a mutation.
