Which of the following is not a required test for the deduction of a business expense?

The deduction of a business expense must meet specific criteria to be considered valid under tax law. The tests that are required include the predicates of being "ordinary," "necessary," and "reasonable."

An ordinary expense is one that is common and accepted in the taxpayer's trade or business. A necessary expense is one that is appropriate and helpful for the business, while a reasonable expense refers to the idea that the amount spent is not excessive for the services or products provided.

The concept of "unavoidable," however, is not a criterion for deductibility. While business owners strive to avoid unnecessary expenses, the IRS does not require that business expenses be unavoidable for them to be deductible. This means that as long as the expenses are ordinary, necessary, and reasonable, they may still be deducted even if they could have been avoided in other ways, thus making "unavoidable" the correct choice for what is not a required test for the deduction of a business expense.