How to use title in salutation, when recepient's name is unknown

I'm sending a formal letter to an adjudicator but do not know his or her name. What would be the most appropriate salutation?

Dear Adjudicator:
Dear adjudicator:
Dear sir or madam:
To whom it may concern: 

unknown gender
To whom it may concern - unknown post (Adjudicator in this case)

[from address]

[date]

The Adjudicator
[to address]

Dear Sir or Madam

Preferably, Dear [name with title]

I would address it

To the Adjudicator.

This is nice and specific and lets the recipient know that the letter is specifically intended for them, as opposed to a general 'Dear Sir/Madam' or 'To whom it may concern' which could be received by anybody.