an observation a prediction a conclusion a theory a hypothesis
I gave my students this multiple choice question: Sally placed electrodes into a beaker containing a solution and connected the electrodes to a batter. Part of Sally's report stated "Bubbles were given off at one of the electrodes." The statement is

Only one answer is correct among these 4 choices:
- an observation
- a prediction
- a conclusion
- a theory
- a hypothesis

Could you tell me which one is correct?

an observation