Answer:
c The double coincidence of wants was not satisfied.
Step-by-step explanation:
As in the given question, it is mentioned that Gina is not willing to help to teach his kids so that the kids could able to learn British accent so in this case the kids are unwilling to help her to mow her lawn that represents there is an absence of double coincidence. Also she does not have flat money
So in this case no economic activity existed due to the absence of double coincidence
hence, the correct option is C.