Answer:
A. title
Explanation:
These are mostly associated to magazines and newspaper, but it's not a rule. Generally speaking, a letter to the editor is a letter that is sent to a publication in order to talk about the concerns that a reader might have. Generally speaking, they are intended for publication. As any letter, it would be very uncommon to have a title in it, but it does need a heading, greetings, and an address as you'd generally do in formal letters.
