Which of the following best defines a material breach?

A material breach is defined as a significant violation of a contract that undermines the contract's overall purpose and effectiveness. This type of breach typically entitles the non-breaching party to either terminate the contract or seek damages because it fundamentally disrupts their expected benefits under the agreement.

In contrast, other options reflect misunderstandings of what constitutes a material breach. A trivial breach, for example, does not significantly impact the contract's intent and usually does not warrant legal action. The notion of a rare occurrence in business agreements overlooks the reality that material breaches can be frequent in practice, particularly in complex contracts. Lastly, an acceptable deviation from contractual terms suggests some flexibility that does not align with the concept of a material breach, which is characterized by a clear failure to meet significant contractual obligations.

Therefore, identifying a breach as material requires evaluating its significance and the extent to which it affects the contractual relationship, making the selected answer the correct interpretation.