## **Core Concept**
The question tests the understanding of the basic structural components of nucleic acids, specifically focusing on the type of pentose sugar present in DNA and RNA. Nucleic acids are composed of nucleotides, each containing a phosphate group, a nitrogenous base, and a pentose sugar. The two main types of pentose sugars found in nucleic acids are ribose and deoxyribose.

## **Why the Correct Answer is Right**
The correct answer, , refers to deoxyribose, which is the pentose sugar found in DNA (deoxyribonucleic acid). Deoxyribose is a five-carbon sugar that differs from ribose by having one less oxygen atom. This sugar is a key component of the DNA backbone, linking with phosphate groups to form the nucleic acid's phosphodiester backbone. The presence of deoxyribose in DNA is crucial for its stability and function.

## **Why Each Wrong Option is Incorrect**
- **Option A:** - This option refers to ribose, which is the pentose sugar found in RNA (ribonucleic acid), not DNA. While ribose is indeed a pentose sugar in nucleic acids, the question specifically asks for the pentose sugar in nucleic acid, implying a broader context that could include both DNA and RNA but is often understood to highlight DNA.
- **Option C:** - This option seems to represent another sugar or a derivative but is not accurately identified as a common pentose sugar in nucleic acids.
- **Option D:** - Similarly, this option does not correspond to a recognized pentose sugar in the context of nucleic acid structure.

## **Clinical Pearl / High-Yield Fact**
A crucial point to remember is that DNA contains **deoxyribose**, while RNA contains **ribose**. This distinction is fundamental to understanding the structural and functional differences between DNA and RNA.

## **Correct Answer:** . deoxyribose