Correct option is (a) separate DNA
Explanation: An electrophoresis machine uses the charge present on the substance and the weight of the substance to separate the various components of the substance. The DNA strand is taken and broken at various places which is detected by markers. These strands all possess individual charges and weights. When a potential difference is developed across the two ends, the strands start moving according to their weight and charges. Thus, the strands of the DNA get separated.