Read the following passage and answer the questions that follow:-
Deeksha lives in a society where a robbery occurred last night. Robbers came into the flat and murdered the old lady residing there. Police came and restricted the entry into the flat. They took samples from the room, where the dead body was found. While examining, they found that there is some blood and tissue in the nails of an old lady. According to their observation, police filtered out their inspection to three suspects viz. servant, cook, and milkman. Finally, after two days of robbery, police caught the criminal. It was the old lady’s cook. Deeksha was amazed to see how quickly the police completed and shut the case. She asked the inspector how they did it? The policeman told her that it become possible due to the sample collected from the victim, which lead them to the criminal. The sample taken from nail scraping was amplified using PCR and then tested.

What technique was used by the police to identify the criminal?

DNA fingerprinting.

The correct answer is Option (2) -DNA fingerprinting.

The technique used by the police to identify criminals among the options provided is DNA fingerprinting. DNA fingerprinting, also known as DNA profiling or DNA typing, is a molecular biology technique that analyzes specific regions of an individual's DNA to create a unique identifier, or "fingerprint." This technique is commonly used in forensic science to match biological samples found at a crime scene with the DNA of a suspect or to establish biological relationships between individuals.

Gel electrophoresis and molecular diagnosis are related techniques used in molecular biology and genetics, but they are not specific to criminal identification.

Cloning, on the other hand, is a different biological process used to create identical copies of DNA fragments, genes, or entire organisms and is not typically used in forensic identification of criminals.