**Core Concept**
In vitro DNA amplification is a laboratory technique used to generate multiple copies of a specific DNA sequence from a small initial sample. This process involves the use of enzymes to replicate the target DNA sequence, resulting in a significant increase in the number of copies. Polymerase chain reaction (PCR) is the most commonly used method for in vitro DNA amplification.

**Why the Correct Answer is Right**
The correct answer is **B. Polymerase Chain Reaction (PCR)**. PCR is a thermal cycling process that uses two primers, a DNA polymerase, and nucleotides to amplify the target DNA sequence. The process involves denaturation of the DNA template at high temperatures, annealing of the primers to the template at lower temperatures, and extension of the primers by the DNA polymerase at an intermediate temperature. This cycle is repeated multiple times to achieve exponential amplification of the target DNA sequence.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a particular method for DNA amplification. While it may be a general term, it does not accurately describe a specific technique.
* **Option C:** This option is incorrect because it refers to a different laboratory technique, DNA sequencing, which is used to determine the order of nucleotides in a DNA sequence. While DNA sequencing is an important tool in molecular biology, it is not used for DNA amplification.

**Clinical Pearl / High-Yield Fact**
One important consideration when performing PCR is the need to prevent contamination with extraneous DNA, which can occur through various means, including skin cells, clothing, and laboratory equipment. To minimize the risk of contamination, it is essential to use aseptic techniques and to handle the reaction tubes and reagents carefully.

**Correct Answer: B. Polymerase Chain Reaction (PCR)**