Scenario 8-2 Tom Mows Stephanie's Lawn for $25. Tom's Opportunity Cost of Cost

Scenario 8-2
Tom mows Stephanie's lawn for $25. Tom's opportunity cost of mowing Stephanie's lawn is $20, and Stephanie's willingness to pay Tom to mow her lawn is $28.
-Refer to Scenario 8-2.Assume Ryan is required to pay a tax of $10 each time he mows a lawn.Which of the following results is most likely?

A) Stephanie now will decide to mow her own lawn, and Ryan will decide it is no longer in his interest to mow Stephanie's lawn.
B) Stephanie still is willing to pay Ryan to mow her lawn, but Ryan will decline her offer.
C) Ryan still is willing to mow Stephanie's lawn, but Stephanie will decide to mow her own lawn.
D) Ryan and Stephanie still can engage in a mutually-agreeable trade.