An example of a breach of a purchase contract is

A breach of a purchase contract occurs when one party fails to fulfill their obligations as outlined in the agreement. In this context, the clear example of a breach is the failure to close the transaction without a legal excuse. This means that one party has not met the contractual requirement to complete the sale by the agreed upon date and for reasons that do not comply with what's stipulated in the contract, thus affecting the other party's rights and interests.

The other scenarios, while they can complicate a real estate transaction, do not directly constitute a breach of the contract itself. For instance, the failure of a property to appraise affects financing and may lead to negotiations or adjustments, but it isn't an outright breach of a purchase contract. Similarly, if a lender cancels a loan program, it may impact the buyer's ability to secure financing, but it does not mean that the parties involved in the contract have failed to perform their obligations as described in the contract. Therefore, the correct example of a breach specifically relates to the failure to close the deal without any legal justification.