What is a valid alteration in a contract?

In the context of contract law, a valid alteration occurs when the original terms of a contract are modified in a way that creates a new agreement between the parties involved. The correct answer emphasizes that a valid alteration not only discharges the original contract but also establishes binding new terms that both parties have agreed to.

This process typically requires mutual consent, meaning both parties must agree to the changes to ensure that the new terms are enforceable. When the original contract is discharged, it effectively loses its binding effect, and the parties are expected to adhere to the revised agreement. This understanding is crucial because it illustrates the significance of intending to create a new legal relationship based on the modified terms.

In contrast, the other options do not reflect the legal principles governing contract alterations. Modifying non-essential terms does not necessarily create a new binding agreement, unilaterally changing terms is typically not valid without the consent of the other party, and minor adjustments that need no consent do not accurately represent the necessity for mutual agreement in contract law. Thus, the focus on mutual consent in option B aligns with the foundational principles of how alterations must function legally.