Which of the Following Is True of Gene Therapy

Which of the following is true of gene therapy?

A) Gene therapy has proven to be successful with a wide range of diseases and is often the only hope for a cure.
B) Gene therapy is widely viewed as unethical and is illegal in the United States.
C) Because many diseases are the result of multiple genes and their interactions with other genes and the environment,gene therapy is unlikely to produce quick cures.
D) Gene therapy has failed virtually every time it has been tried and has fallen out of favor with clinical researchers.