The correct answer is (a). Microsatellite DNA is a type of repetitive DNA that is found in all eukaryotic organisms. It is composed of short, tandem repeats of 1-6 nucleotides. Microsatellite DNA is highly variable, and this variation can be used to study the evolutionary relationships among various species of fauna.
(b) is incorrect because microsatellite DNA is not used to stimulate stem cells to transform into diverse functional tissues. This is done by using other types of DNA, such as transcription factors.
(c) is incorrect because microsatellite DNA is not used to promote clonal propagation of horticultural plants. This is done by using other methods, such as tissue culture.
(d) is incorrect because microsatellite DNA is not used to assess the efficacy of drugs by conducting series of drug trials in population. This is done by using other methods, such as clinical trials.