The shop stocked four sweets and, as you can see from the pictures, none were sold on day one or day two.
On the third day, one was sold.
Look at the pictures to work out which suit is on the pink side of the sweet that was sold.
The pictures from day one and day two show the front and back of all of the sweets.
None of the sweets have the same suit on both sides.
No suit appears on the same colour twice either.
The sweet that was sold is pictured on day one, with a spade on a blue backgroud.
If you look at the two pictures, you can see that its pink side has to be either a diamond or a club.
Continuing on from hint three...
The picture from day three shows that the sweet with a diamond on its pink side is still unsold.
That means that the sweet that was sold can't have had a diamond on its pink side.
Answer for 'Sweet Suits'
The answer is 'C'.