At a listing appointment, Patty promises the sellers they will get four open houses a month. The seller signs the agreement. In the first month of marketing, Patty's husband becomes ill and Patty cancels the open house. The seller got only two open houses that month. Which best describes the situation?
a) Patty fulfilled her obligation
b) Patty breached the contract
c) Patty can reschedule the open houses
d) Patty's personal reasons justify the cancellation