Where Does the Dateline Go on a Letter

Where does the dateline go on a letter?

A) Two or three lines below the letterhead, about fifteen lines (2-1/2 inches) down the page
B) Right below the letterhead, about twelve lines (2 inches) down the page
C) To the right of the letterhead, at the same level with the last line on the letterhead
D) One line above the letterhead
E) None of these