**Core Concept:** Single base pair substitution is a type of mutation where one nucleotide is replaced by another in the DNA sequence. Oligonucleotides are short sequences of nucleotides that can be used for various molecular biology applications, including genetic testing.

**Why the Correct Answer is Right:** The correct answer is "D. Polymerase Chain Reaction (PCR)". PCR is a molecular technique used to amplify specific DNA sequences. In the process of PCR, an oligonucleotide primer is designed to bind to the target DNA sequence on either side of the single base pair substitution. By using a thermostable DNA polymerase enzyme, the primers anneal to the target DNA, and the polymerase extends the primers, generating multiple copies of the DNA segment containing the mutation.

**Why Each Wrong Option is Incorrect:**

A. **Mutation Scoring System (MSS)** - This is a method used to determine the frequency of mutations in a population, not a test that detects mutations directly.

B. **Single Strand Conformation Polymorphism (SSCP)** - SSCP is a technique used to detect DNA polymorphisms, not mutations specifically. It involves separating DNA fragments based on their conformation, but it does not specifically target single base pair substitutions.

C. **Sanger Sequencing** - Although Sanger sequencing is a method for determining the sequence of nucleotides in a DNA molecule, it does not specifically target single base pair substitutions. It provides information on the entire DNA sequence, not just the mutation of interest.

**Clinical Pearl:** PCR is a highly sensitive and specific technique for detecting genetic mutations, including single base pair substitutions. It is widely used in clinical genetics, research, and diagnostic settings. Understanding the principles of PCR and designing appropriate primers is crucial for accurate mutation detection.

**Correct Answer Line:** Correct Answer: **D. Polymerase Chain Reaction (PCR)**