The correct answer is option 4, Southern Blotting.

Let`s dissect each option to understand why option 4 is the correct one.

Option 1, ELISA: Enzyme-Linked Immunosorbent Assay (ELISA) is a technique used for detecting and quantifying proteins or antibodies, not DNA. Therefore, ELISA is not the technique used for DNA fingerprinting.

Option 2, RIA: Radioimmunoassay (RIA) is a technique that uses radioactive isotopes to measure the concentration of specific substances, such as hormones or drugs, in a sample. RIA is not used for DNA fingerprinting.

Option 3, Northern Blotting: Northern blotting is a technique used to study gene expression by detecting and analyzing RNA molecules. It is not used specifically for DNA fingerprinting.

Option 4, Southern Blotting: Southern blotting is a method used to detect and analyze specific DNA fragments. It involves transferring DNA from a gel to a membrane and then using labeled DNA probes to identify specific sequences. This technique is commonly used for DNA fingerprinting, making option 4 the correct answer.

Therefore, the technique used for DNA fingerprinting is Southern Blotting.