Probably a little column A, a little column B

depends on the force of your stream and how close you are to the surface of the water

You could taste some and find out?

It’s both.

Here’s a video of a water droplet, and you can see water (or urine) can actually bounce off the surface: https://www.youtube.com/watch?v=pbGz1njqhxU

And here’s a simulated urine stream: https://www.youtube.com/watch?v=9c66KVU5ah8

The urine displaces a lot of nearby water as well. That surrounding water would initially be “clean” toilet water, but urine will mix into the water pretty quickly. That mixed water will then also displace as more urine hits the surface.