A door-to-door salesperson knocks on Mary's door and convinces her to purchase the Wonder Vacuum for $500. Soon after the salesperson leaves, Mary begins to have second thoughts about the transaction. Which statement about the situation is correct?a. Mary agreed to purchase the vacuum, so she must honor the agreement. b. Mary must pay for the vacuum, but she can get a refund if she returns it to the manufacturer within 30 days. c. Mary can keep the vacuum without paying when it is delivered, as it was purchased in her home. d. Mary can cancel the transaction at any time before midnight of the third business day thereafter.