This scoped C96 carbine is serial number 12 of the original run of just 30 large-ring C96 carbines. It has the long barrel and detachable stock (in place of the standard pistol grip) of the C96 carbine. The most obvious feature, however, is the telescopic sight mounted on the piece. This was not installed by the Mauser factory, but was added around the time the carbine was originally purchase. The scope and mounts are of the same vintage as the gun (right around 1900).
The scope mount is a quick-detachable claw style typical of German sporting arms, and it fits the C96 carbine quite well. The eye relief and scope height both fit nicely with the stock position, and I expect this would be a very nice and comfortable piece to shoot.
In many ways, this reflects the same type of use we see today with pistol-caliber carbines and low-power compact optics. People assume that tactical is a new thing, but it really isn;t – they just did it more stylishly a hundred years ago.