Fill in the Blank Spaces in Each of the Following

Fill in the blank spaces in each of the following sentences about the business letter.
A) In Australia, showing the date as 9/10/04 means 9 October 2004, whereas in the US it would mean ________.
B) The attention line of a business letter directs the letter to ________.
C) In writing the salutation, if you do not know the person you are writing to, you should address them as ________.
D) The purpose of a reference line is to ________.
E) For formal letters, an appropriate signature is ________.