Suppose you are interested in finding the causal effect of weekly injections of 800mg of testosterone cypionate in Chad's bench press. Chad takes the steroids for 16 weeks. Which of the following is the best counterfactual?

a)Chad's bench press increase after 16 weeks had he NOT taken the testosterone.

b) Chad's bench press increase over 16 weeks exactly one calendar year ago.

c) Brad's bench press increase over the same 16 weeks as Chad's workout partner, except Brad doesn't use testosterone.

d)What Chad thinks would have been the increase in his bench press over the 16 weeks had he not used testosterone.

e) All of the above counterfactuals are pretty bad.