#3 John Nunn's Favourite Puzzles

Here we are! The third problem:
White to Play and Mate in Two.

#2 Problem - Hint

Okay, since no one has posted the solution
to the second problem I give you the hint:
"The first point to note is that Black's king has a possible escape route to e4, so White's first move must either prevent Ke4 or prepare a reply to it. The second point is that if White loses control of c4 or e6 then Black can give a discover check by moving his king. However composers love an element of paradox in their problems, so..."
(taken from Chessmaster 9000)

#2 John Nunn's Favourite Chess Puzzles

Ok, the first one was really too easy, so I post the second which is both more difficult and more instructive. I think resolving a problem is very useful to gain confidence, develop calculation ability and tactical intuition. So, why not to try? If you cannot find it, I'll give you a hint in a couple of days.
WHITE TO PLAY AND MATE IN TWO.

#1 John Nunn's favourite chess puzzles

I'll post once a week a problem taken from '50 John Nunn's favoutite chess puzzles'. (They're all 'WHITE TO PLAY AND MATE IN TWO').
Post the solution in the comments (don't use engines please!).
Let's start with an easy one: