**Core Concept**
Western blotting is a laboratory technique used to detect and analyze proteins in a sample. It involves separating proteins by size using gel electrophoresis, transferring them to a membrane, and then probing with antibodies to identify specific proteins.

**Why the Correct Answer is Right**
Western blotting is a powerful tool for identifying proteins, particularly in the context of detecting antibodies or antigens in serum or tissue samples. The technique relies on the specific binding of antibodies to their target antigens, allowing researchers to detect and quantify protein expression. In many cases, Western blotting is used to confirm the presence of a specific protein or to investigate protein expression patterns in response to various stimuli or disease states.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Western blotting is not typically used to identify nucleic acids, such as DNA or RNA. Techniques like PCR (polymerase chain reaction) or Southern blotting are more commonly used for this purpose.
**Option B:** This option is incorrect because ELISA (enzyme-linked immunosorbent assay) is a different laboratory technique used to detect and quantify specific antibodies or antigens in a sample. While ELISA can be used to identify proteins, it is not the same as Western blotting.
**Option C:** This option is incorrect because immunohistochemistry (IHC) is a technique used to localize and visualize specific proteins or antigens in tissue sections. While IHC can be used to identify proteins, it is not the same as Western blotting.

**Clinical Pearl / High-Yield Fact**
When interpreting Western blot results, it's essential to consider the specificity and sensitivity of the antibodies used, as well as the quality of the sample and the experimental controls. This can help ensure accurate and reliable results.

**Correct Answer:** D.