Elution is

Options

A. The process of coating of DNA with micropellets of gold and tungsten
B. The process of precipitation of DNA using a suitable reagent
C. The process of insertion of DNA
D. The process of cutting out and extracting bands of DNA from gel.

Answer

### Step-by-Step Solution:

1. **Understanding Elution**: Elution is a process used in various biochemical applications, particularly in the extraction and purification of biomolecules like DNA, RNA, and proteins. It involves washing out a substance that is bound to a solid phase, allowing it to be collected in a liquid phase.

2. **Analyzing Options**:
- **Option 1**: "Coating of DNA with micro pellets of gold and tungsten" - This is not related to elution. This option is incorrect.
- **Option 2**: "Precipitation of DNA using a suitable reagent" - Precipitation refers to the process of forming a solid from a solution, which is not the same as elution. This option is incorrect.
- **Option 3**: "Insertion of DNA" - This does not describe elution. This option is incorrect.
- **Option 4**: "Cutting out and extracting parts of the DNA from gel" - This accurately describes the elution process, where DNA bands are cut out from a gel and extracted into a solution for further analysis. This option is correct.

3. **Conclusion**: Based on the analysis of the options, the correct answer is **Option 4**, which describes elution as the process of cutting out and extracting parts of the DNA from gel.