Informed consent:

a) A study plan on which all clinical trials are based.

b) Any of the treatment groups in a randomized trial.

c) The process of learning the key facts about a clinical trial before deciding whether or not to participate.

d) A modification of the effect of the drug when administered with another drug.

e) None of the above.

c) The process of learning the key facts about a clinical trial before deciding whether or not to participate.

Explanation:

Informed consent can simply be explained as a situation whereby the participants or people that have decided to take part in a clinical trial have been initially informed about the purpose, benefits and risk associated with the trial they are about get involved in.

It can also be put as the process by which a patient learns about and understands the purpose, benefits, and potential risks of a medical or surgical intervention, including clinical trials, and then agrees to receive the treatment or participate in the trial.

In conclusion, it is important that the benefits and risks of a procedure are explained to a patient or guardian, and then they give permission for a medical procedure to take place.

It should be understood that patients have the right to either give informed consent or to refuse.

Option C is correct.

Explanation:

The process of learning the key facts about a clinical trial before deciding whether or not to participate.