Setting the overlap

I created a game where balls appear and pumps,

I put the bombs in the layer below the layer of balls.

but when I click a ball that is right on top of a bomb, instead of clicking on the ball, is the pump that is activating.

I’m using Box Collider in both object and sorting layer.

I’m using Unity 5

to recognize the touch’m using: void OnMouseDown()

my game is in play store, who wants to download and play, be my guest. if you do not like the game, please do not give bad score because it is my first game, I’m still learning.

I managed to solve this problem,

excuse the delay in posting the resolution. What I did was put all objects on a single layer and change the position “Z” of each. It worked.