A vector is a DNA molecule used to carry additional genetic material into a cell. A vector that carries foreign DNA is called recombinant DNA. There are four types of vectors including cosmids, viral vectors, plasmids, and artificial chromosomes.
The most common vectors are plasmids that are used for cloning, although some of them are designed specifically for cloning. Restriction enzymes are used to cut DNA, and these are found in bacteria, which eliminates choice A. Polymerase chain reaction is used to make millions of copies of DNA.