Final answer:
Gel electrophoresis is the technique used to separate DNA fragments by size after they have been cut by restriction enzymes, and it results in a banding pattern on an agarose gel that can be visualized.
Step-by-step explanation:
The technique that separates DNA into different patterns based on DNA fragment sizes created by restriction enzymes is gel electrophoresis. In this process, DNA is first treated with specific restriction enzymes to produce fragments, which are then separated on an agarose gel due to the electric field applied across the gel. This separation occurs because smaller DNA fragments move more rapidly through the gel, and each fragment's movement is affected by its size. After the electrophoresis, the fragments can be visualized, often with a fluorescent dye such as ethidium bromide, resulting in a banding pattern that can be compared to a DNA ladder containing fragments of known size.
Agarose gel electrophoresis is a key technique in molecular biology for analyzing DNA. It is useful in various applications, including Restriction Fragment Length Polymorphism (RFLP) analysis, where the pattern of DNA fragments after digestion with restriction enzymes can provide valuable genetic information. The correct answer to the student's question is therefore c) Gel electrophoresis.