You Have Been Asked to Help a Top Nutrition Researcher

You have been asked to help a top nutrition researcher conduct human double-blind experiments on vitamin C. As the subjects walk into the laboratory, you distribute all the vitamin C pill bottles to the girls and all the placebo pill bottles to the boys. The researcher instantly informs you that there are two errors in your research practice. What steps should you have taken to conduct your experiment correctly?

A) You should have given all the boys the vitamin C and all the girls the placebo and then told them what they were getting.
B) You should have distributed the bottles after randomly assigning the subjects and then told them what they were getting.
C) You should have told the subjects which group they were in, while preventing yourself from knowing the contents of the pill bottles.
D) You should have prevented yourself from knowing what was in the pill bottles and distributed the bottles randomly to the subjects.
E) You should have allowed the subjects to decide whether they take vitamin C or the placebo, and then given them the opposite of what they requested.