Which of the following can lead to a breach of contract?

A breach of contract occurs when one party fails to fulfill their obligations as outlined in the agreement. This means that option B is a direct and clear representation of what constitutes a breach: the failure to perform the contractual obligations as specified. When one party does not adhere to the terms of the contract—whether through non-performance, late performance, or incomplete performance—it results in a breach, which can lead to legal consequences such as damages or specific performance.

While changing market conditions and misinterpretation of the contract can affect the contract’s execution or the parties' understandings, they do not inherently constitute a breach in the same way that failing to perform obligations does. Changing market conditions might lead to difficulties in performance or make performance less advantageous, but they do not automatically excuse non-performance or failure to meet obligations. Misinterpretation could lead to disputes about what the terms were intended to mean, potentially complicating enforcement but not typically leading to a breach unless it results in a failure to perform.

Thus, the failure to perform obligations as specified is the clearest, most direct cause of a breach of contract, making it the best answer.