Answer:
The answer is A: No, because they did not know the nature of the experiment before participating
Explanation:
If you look at the lesson's clear definition of informed consent, you can see that the participants are to be informed of what exactly the experiment entails. Only after this can the researchers get informed consent. Usually, for minors, permission is obtained from parents or guardians, but the question does not give any details about this, only that the high schoolers signed up for this. Since the prompt does not tell us that the high schoolers were informed about the nature of the experiment before they signed up, we can safely assume, they did not give informed consent.