Which of the following best describes a complete instrument?

A complete instrument, in the context of financial transactions or legal documents, refers to an item that meets all the necessary requirements to be fully valid and enforceable. A signed and filled-out check fits this description perfectly because it contains all the essential elements: the date, the payee's name, the amount, and the signature of the account holder.

When these elements are all present, the check can be processed and is legally binding, allowing the payee to present it for payment. This makes it a complete financial instrument, as it fulfills its intended function without any additional requirements.

On the other hand, a blank check lacks the specific details needed, such as the payee's name and the amount, rendering it incomplete. A verbal agreement does not provide the tangible documentation necessary for execution and enforcement in most scenarios, which is less reliable. An unsigned contract also fails to constitute a complete instrument since the lack of a signature means there's no formal agreement established. Thus, the choice of a signed and filled-out check as the best representation of a complete instrument is correct, as it encompasses all the necessary elements for valid financial execution.