How Do Scientists Compare People's DNA

How do scientists compare people's DNA?

A) Because scientists know what genes correspond to what physical traits, they can compare people's DNA by just comparing the traits they see.
B) Scientists collect the DNA and using an electron microscope, straighten out the strands from different people and compare them by looking at them.
C) Scientists collect the DNA, chop it up into pieces, and use chromatography to compare them. Different genes show up in different colored bands which can be compared person to person.
D) Scientists assemble a pedigree for the people they're comparing, and this allows them to compare their DNA.
E) Scientists collect the DNA, chop it up into pieces, and use electrophoresis to separate the genes according to their electrical charge. The genes show up in bands which can be compared person to person.