Answer:
The correct answer is that is by repeated the experiment many times.
Step-by-step explanation:
In the given case, as the scientist performed one trial of an experiment and received an unexpected outcome, thus, there is a need to repeat the experiment and to observe that whether he is getting the similar result or not. If the obtained result is still similar and is not matching the expectations of the scientist, then there is a need to repeat the experiment again and to discuss the outcomes with some other scientists. If the result comes different, then one should look for the cause of the error.