How Does a Scientist Get the Corrected Version of a Gene

How does a scientist get the corrected version of a gene into the cells of a gene therapy patient?

A) It is delivered with a modified virus.
B) It is directly injected with a microscopic hypodermic needle.
C) By attaching it to a food molecule,like glucose,it is then ingested by the individual.
D) By attaching it to the surface of microscopic beads,it is then shot into the individual (i.e.,shotgun method) .