repeat the experiment and check for errors change the observations to match the hypothesis redo the experiment until the expected results are obtained record and analyze the data after changing the hypothesis
I gave my students this multiple choice question: What should be done when the results of an experiment do not support the hypothesis?

Only one answer is correct among these 4 choices:
- repeat the experiment and check for errors
- change the observations to match the hypothesis
- redo the experiment until the expected results are obtained
- record and analyze the data after changing the hypothesis

Could you tell me which one is correct?

repeat the experiment and check for errors