C. The scientific method was followed because the experiment tested the hypothesis and produced reliable results.
Explanation:
The purpose of an experiment is to test the hypothesis. It is true that having an experimental group and a control group was following the scientific method but the data gathering and documentation was also part of the scientific method. So the best answer would be C.
Writing the question is not necessary. It is merely part of forming a hypothesis. The scientific method does not require many scientists to perform the experiment, but it does require that the experiment be repeatable, so it can be tested again.
