Which of the following is NOT a component of a business letter?

In the context of a business letter, the components that are typically included are the date, body, and closing. The date indicates when the letter was written, the body contains the main content or message being communicated, and the closing serves as a polite way to end the letter, often followed by the sender's name and signature.

An appendix, on the other hand, is not a standard component of a business letter. While it might be used in reports or academic papers to provide additional information or supporting materials, it doesn't generally belong in the structure of a business letter. A business letter is designed to be direct and concise, focusing on the message at hand rather than supplementary information. Hence, the inclusion of an appendix would be considered outside the conventional components of a business letter.