Find my iPhone: how to identify each device?
It's too late now to identify the iPhone.  This must be done prior to losing the device, when you're able to provide a name for it.  Find iPhone doesn't list the specific device.

To name the device, go to Settings -&gt; General -&gt; About and in the Name field enter a specific device name (for example, 'PaulJ's iPhone 5s').  Then, when you need to locate the device, it will get the name you entered and it can be identified.

The only thing you can do now is the process of elimination.  Figure out which of the 3 devices listed is not accounted for someplace or, perhaps, not turned on.