The question requires us to specify the product obtained when the Photosystem II splits water.
First, we need to remember that splitting water means "breaking" water into its components.
In that sense, water splitting is the chemical reaction where water is broken down into oxygen and hydrogen:
With that concept in mind, we can say that the photosystem II will produce oxygen (option A).
Another important thing to remember about this system is that it captures photons (the energy from the light) and uses this energy to extract electrons from water.