The answer to your question is c.invented because it's a past participle.
Answer:
The goal of the experiment was to observe how far the participants were willing to obey the experimenter, even though what they were doing was morally wrong
Explanation:
In this excerpt from Leo Tolstoy’s "The Death of Ivan Ilyich", the sentences that best shows how Ivan Ilyich struggles with his life and his inability to let go of his past are:
"He was hindered from getting into it by his conviction that his life had been a good one. That very justification of his life held him fast and prevented his moving forward, and it caused him most torment of all."
In this two sentences, we can see that Ivan Ilyich cannot comprehend what is happening to him if his life had been so god. His past happiness does not allow him to accept his current situation. Ivan Ilyich is aware of this incapacity of letting go of his past and feels frustrated and depressed because of it.
