Roland mows Karla's lawn for $$25.$ Roland's opportunity cost of mowing Karla's lawn is $$20,$ and Karla's willingness to pay Roland to mow her lawn is $$28.$

Refer to Scenario $8-2.$ Assume Roland is required to pay a tax of $$3$ each time he mows a lawn. Which of the following results is most likely?

a$.$ Karla is willing to pay Roland to mow her lawn, but Roland will decline her offer.

b$.$ Karla now will decide to mow her own lawn, and Roland will decide it is no longer in his interest to mow Karla's lawn.

c$.$ Roland is willing to mow Karla's lawn, but Karla will decide to mow her own lawn.

d$.$ Roland and Karla still can engage in a mutually$-$agreeable trade.