Find the correct statement(s) from the following.
I. Gene therapy is a genetic engineering technique used to treat diseases at molecular level.
II. Calcitonin is medically useful recombinant product in the treatment of infertility.
III. Bt toxin is a biodegradable insecticide obtained from Bacillus thuringiensis.

(i) Gene therapy has been tested on a large number of patients with a wider variety of inherited genetic disorders, and in numerous cases it has produced a complete cure.
(ii) Genetic engineering has been used to produce insulin for curing the diabetes.
(iii) DNA hybridization is the base pairing of DNA from two different sources
(iv) Genetic engineering is a technique of plant breeding.