Which of the Following Is the Strongest Challenge to the Two-Process

Multiple Choice

Which of the following is the strongest challenge to the two-process theory account of free-operant avoidance learning?

A) Avoidance behavior can be conditioned when S-S and R-S intervals are varied throughout an experiment.
B) There is no explicit CS in free-operant procedures.
C) With extensive training, subjects distribute their responses towards the end of the R-S interval.
D) S-S and R-S intervals are typically quite predictable.