Give one word for the following expression: A letter, poem, etc. whose author…

Solution: The correct answer is 'Anonymous'.

Meaning: Anonymous — a letter, poem, etc. whose author is unknown.

Example: She received an anonymous letter.

Why the other choices are incorrect:

• Autobiography — a life story written by the person themselves (author known).

• Catalogue — a list of items (books, products, etc.), not related to unknown authorship.

• Biography — a life story written by someone else (the writer is identified), so it does not mean the author is unknown.