Find the different one
You are standing in front of a framed picture hanging on the wall.
Inside the frame is the following image:
On the left, three pictures are arranged vertically.
To the right of each picture, a large alphabet letter is written.
There is a picture of an apple, with the letter A next to it.
There is a picture of a cat, with the letter C next to it.
There is a picture of an elephant, with the letter ? next to it.
Below the frame, several buttons are embedded in the wall.
Which button will you press?