Which is most scientific?

一个pharmaceutical company has a new drug they want to test to determine its efficacy. They have a hypothesis that this drug is super effective at curing a disease. Which of the following experiments/results best reflects the principles of the scientific method? Which is most scientific?

一个) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, they strictly controlled these patient's diet, limited other medication, and 77 of the subjects reported that their happiness improved significantly.

B) They found a remote island with an indigenous population that's genetically different from other populations and where 200 patients have the disease. They gave 100 patients on the island the drug and 100 a placebo. They strictly controlled these patient's diet, limited other medication, and found that 84 of the test patients had higher red and white blood cell count than the control group, and lower incidents of mortality from the disease than non-island populations.

C) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, they strictly controlled these patient's diet, limited other medication, and found that only 5 of the test patients had higher red and white blood cell count than the control group, with no other changes in health.

D) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, allowed both patients to consume and medicate in whatever way those patients desired, and found that 68 of the test patients had higher red and white blood cell count than the control group, with faster speed-to-recovery.