Answer:
d. Autoradiographies
Step-by-step explanation:
Based on the information provided within the question it can be said that the technique that is mainly used for this are Autoradiographies. This is a technique that is mostly used for X- ray film to visualize molecules or fragments of molecules that have been radioactively but are also used for analyzing the length and number of DNA fragments using a special method called gel electrophoresis which is then used to compare the various DNA samples.