1 Move Mate

Qa3

Wf4

Gg

Q-d6#

i repeat Q-d6#

Q-d6# is the only mate in one!!

Black goes Kd8.

Qxe5 is not mate because black can do Be6.

Technically it is mate, although not the fastest one.

I meant mate in 1

Bh4 seems like the only one that makes sense to me

Ng6? 

Hi. How can I add?

The staggering volume of incorrect answers proves the OP's point.  Nice problem!

I just got back from an early morning meeting where the topic was agenda driven. One party didn't like the use of the term "incorrect". I think you are supposed to say "alternative expression". 

No B(b1) x g6 in that case

No because of Rg1 - g5 blocks it

d8=Q or exc8=Q

The d7 pawn is pinned and cannot move

It can capture the pinning piece (and promote to a queen while giving a discovered check) but Bh1b7 blocks the check).