**Core Concept**
Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific DNA sequences. It involves the use of enzymes, primers, and thermal cycling to generate millions of copies of a target DNA sequence from a small initial sample.

**Why the Correct Answer is Right**
The correct answer is **b) DNA amplification**. PCR is a method for amplifying specific DNA sequences, making it a powerful tool for genetic analysis. The process involves the use of DNA polymerase, primers, and nucleotides to synthesize new DNA strands. The primers bind to specific sequences on the target DNA, and the DNA polymerase extends the primers, creating a new DNA strand. This process is repeated multiple times, resulting in the amplification of the target DNA sequence.

**Why Each Wrong Option is Incorrect**
* **Option A:** Protein amplification is incorrect because PCR is specifically designed to amplify DNA sequences, not proteins. While proteins can be analyzed using PCR, the technique itself is focused on DNA.
* **Option C:** PCR is not the same as Western blot test. While both techniques can be used to analyze proteins, Western blot is a different method that involves separating proteins by size and detecting them using antibodies.
* **Option D:** Detection of infecting organisms is not the primary purpose of PCR. While PCR can be used to detect the presence of pathogens, it is a more general technique that can be applied to a wide range of genetic analysis.

**Clinical Pearl / High-Yield Fact**
PCR is a highly sensitive and specific technique that can be used to detect genetic mutations, diagnose infectious diseases, and analyze genetic variation.

**Correct Answer: B. DNA amplification**