Amanda is interested in the effect that yoga has on state anxiety. To test this, she randomly assigns 50 college students to either (a) a yoga class that meets once a week for 50 minutes over10 weeks or (b) a control condition. By a very odd coincidence,Richard Simmons happens to overhear theparticipants in the control group lament over not receiving the yoga instruction. Moved by their misfortune, he invites them to attend hispilates class for the next 12 weeks.What threat to validity should Amanda be most concerned with?

Group of answer choices

Unreliability of Treatment Implementation

Interaction of the causal relationship with treatment variation

Fishing

Compensatory equalization