Mark the odd one out w.r.t. the practical use of the tech- nique of PCR :

Options

A. DNA amplification
B. Detection of mutation
C. Nucleotide sequencing
D. All of these are correct

Answer

To solve the question of identifying the odd one out with respect to the practical use of the technique of PCR (Polymerase Chain Reaction), we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand PCR**: PCR is a technique used to amplify small segments of DNA, making millions to billions of copies of a specific DNA sequence. This is crucial for various applications in molecular biology.

2. **Analyze Option 1 - DNA Amplification**:
- PCR is widely known for its ability to amplify DNA. This is a fundamental application of PCR, making it a valid use of the technique.

3. **Analyze Option 2 - Detection of Mutation**:
- PCR can be used to detect mutations in DNA sequences. By amplifying specific regions of DNA, researchers can identify changes in the sequence that may indicate mutations. This is also a practical use of PCR.

4. **Analyze Option 3 - Nucleotide Sequencing**:
- PCR plays a role in DNA sequencing by amplifying the DNA that needs to be sequenced. This allows for the analysis of specific segments of DNA, making this another valid application of PCR.

5. **Analyze Option 4 - All of these are correct**:
- This option suggests that all the previous options (DNA amplification, detection of mutation, and nucleotide sequencing) are correct uses of PCR.

6. **Identify the Odd One Out**:
- Since options 1, 2, and 3 are all valid practical uses of PCR, option 4, which states that all of these are correct, is also valid. However, it does not represent a unique application but rather a summary of the previous options.

### Conclusion:
The odd one out is **Option 4** because it encompasses all the previous options rather than presenting a distinct practical use of PCR.