A section of an exam contains four True-False questions. A completed exam paper is selected at random, and the four answers are recorded.
a. List all 16 outcomes in the sample space.
b. Assuming the outcomes to be equally likely, find the probability that all the answers are the same.
c. Assuming the outcomes to be equally likely, find the probability that exactly one of the four answers is "True."
d. Assuming the outcomes to be equally likely, find the probability that at most one of the four answers is "True."