Which of the following could be a valid reason for contract termination?

A valid reason for contract termination includes mutual agreement of all parties. This method of termination occurs when all parties involved in the contract discuss and agree to end the contract, demonstrating consent from everyone involved to dissolve their obligations without needing to assign fault or breaches. This approach promotes collaboration and respect among the parties and is often seen as an amicable resolution to a contractual relationship.

In contrast, unilateral change of terms is typically not a valid reason for termination, as it implies that one party attempts to change the contract's terms without agreement from the other party, potentially leading to disputes rather than termination. Impossibility of performance can lead to termination but involves specific conditions, such as unforeseen events that prevent a party from fulfilling their obligations, which may or may not be mutual. Material breach by one party also allows for termination; however, it signifies that one party failed to fulfill significant contractual obligations, often leading to conflict rather than a consensual ending. Each of these alternatives does not provide the same level of mutual respect and agreement inherent in the mutual agreement of all parties, making the latter the most straightforward and amicable reason for termination.