Answer: C) She didn't randomly assign participants to the experimental and control groups.
Explanation: It is necessary to randomly assign people to hot or cool units becasue if you give people a choice, they will automatically select the room with the temperature they prefer which would overthrow the point of the experiment.
Hope this helps! :)
It would be "<span>I was present at the sessions of the great Congress in the month of December." He is using that sentence to give credibility to what follows.</span>
An argument is valid only if it takes form in the impossible to make it seem true;)