Which of the Following Is the Main Difference Between in Vivo

Which of the following is the main difference between in vivo and ex vivo gene therapy?

A) Ex vivo gene therapy occurs outside the body and in vivo gene therapy occurs inside the body.
B) Ex vivo gene therapy occurs inside the body and in vivo gene therapy occurs outside the body.
C) Ex vivo gene therapy uses modified DNA of bacterial viruses, where in vivo gene therapy uses the individual's own cells.
D) Ex vivo gene therapy uses modified DNA of bacterial viruses, where in vivo gene therapy uses donor cells.