Boris Purchased Confidential Information from Natasha for a Price of $100

Boris purchased confidential information from Natasha for a price of $100 000.Under the terms of that contract,he was required to pay $5000 on the first day of each month for twenty consecutive months.He was also required,on the first day of each month,to pay 7.5 percent interest on the total amount of the debt that was outstanding.After paying $5000 plus interest for the first month,Boris explained to Natasha that he had suffered a financial setback in his other business ventures.He therefore asked if she would be willing to relieve him of the need to pay interest in the future.Which of the following statements is TRUE?

A) If Natasha says that she will not insist upon the payment of interest in the future,but that promise is not supported by fresh consideration,there is no way that Boris can hold Natasha to her promise.
B) If Boris fails to pay interest in the future,the contract will be frustrated unless Natasha agreed to relieve Boris of the need to pay interest.
C) If Natasha says that she will not insist upon the payment of interest in the future,the doctrine of waiver may later prevent her from changing her mind.
D) The doctrine of waiver would apply in this case only if Natasha promised under seal that she would relieve Boris of the need to pay interest in the future.
E) Since waiver is an equitable doctrine,it would apply to the facts only if a court found that Natasha had acted inequitably or unfairly.