Which of the following is an example of placebo?

* In sham surgery, surgery is done without any purpose; we just open the abdomen in one person and close it, in other person appendix is removed; this is done to see whether appendectomy has any advantage.* Placebos (fake drug/dummy medicine) are used in clinical trials to compare the two treatments; it can't produce any effect. * Herbal medication can produce some effects.* Physiotherapy can also produce effects.