If two business persons or companies enter into an ordinary contract, their respective legal obligations or "duty to perform" under the contract:

Group of answer choices

Can only be "discharged" after both parties have certified in writing that the contract terms have been fulfilled and that some kind of valuable property has been delivered by each contracting party to the other party.

Can be physically impossible, such as by $"$an act of God," and therefore excused as a matter of law.

Can never be waived after both parties have signed the contract and therefore no obligations or duties can be "excused" by either party.