tandem repeats (STRs), also known as refers to a short segment of DNA, one to six or more base pairs in length, that is multiple times in succession at a particular location. DNA sequences are typically non-coding. The of repeated segments within a microsatellite often varies among people, which makes useful as polymorphic markers for studying patterns in families or for creating a DNA from crime scene samples. On the basis of repeat units, STRs can be classified into types. Microsatellites were popularized in genetics during the 1990s because as PCR Chain Reaction) became popular in researches. A microsatellite with a neutral history makes it applicable in important researches. Hence option (a) is the correct