Playfulness is the correct answer
B.
William Shakespeare wrote multiple plays in his life, including Romeo and Juliet.
The correct answer is that they 'are not valid'. If the experiment is biased, it entails that it is not objective. For a experiment, and its results, to be valid, it had to be carried out objectively and taking into account all factors.
It is possible that the results disprove a hypothesis, but to be certain it is necessary to see which was the original objective of the study, as it might also prove to some extent a hypothesis, which is probably also biased.
Yes, there is a few figurative language. Sorry if wrong