**Core Concept**
Protein separation and identification techniques are essential in biochemistry and molecular biology. The process involves isolating and separating protein fragments based on their physical and chemical properties. This is crucial in understanding protein structure, function, and interactions.

**Why the Correct Answer is Right**
Protein fragments separation is often done using techniques such as sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE separates proteins based on their molecular weight, as the SDS (sodium dodecyl sulfate) detergent coats the proteins, giving them a negative charge. This allows the proteins to migrate through the gel based on their size, with smaller proteins moving faster. The process involves the use of a gel matrix, an electric field, and a buffer solution to facilitate the separation of protein fragments.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it doesn't specify a technique for protein fragment separation.
**Option B:** This option is incorrect as it's a technique used for DNA separation, not protein fragments.
**Option C:** This option is incorrect as it's a technique used for protein purification, not separation.

**Clinical Pearl / High-Yield Fact**
A key aspect of protein separation techniques is the use of reducing agents, such as beta-mercaptoethanol, to break disulfide bonds and facilitate the separation of protein fragments based on their molecular weight.

**Correct Answer: A. SDS-PAGE**