In Psychophysical Experiments, It Is Possible to Generate the ROC

In psychophysical experiments, it is possible to generate the ROC function by changing the participant's decision criterion from conservative to liberal. The experimenter can change the decision criterion by

A) changing the probability that a stimulus rather than noise only will be presented.
B) changing the payoffs for hits and false alarms.
C) changing the proportion of trials on which a target is presented
D) all of these.