When Comparing the Responding in the Two Phases Depicted in the Figure

Multiple Choice

When comparing the responding in the two phases depicted in the figure below, the proper interpretation of the second phase would be:

A) that the change in responding in the second phase may represent the effects of the condition itself plus extraneous variables present in the first phase
B) that the change in responding in the second phase is due to extraneous variables
C) that the change in responding in the second phase is due to the introduction of the new condition
D) that the change in responding in the second phase is due to the dependent variable