I have 5 cats and my dog barks at them and she loves them. I don't agree that you should get rid of the cat, the cat was there first. You don't know if the dog even knows what a cat is. You can keep the cat in the basement, but I would still train the dog not to bother the cat, just in case the cat gets upstairs. The dog is well trained, so I would start with leave it, then focus...the dog has to focus on you..not the cat, never the cat.
Misty- Samoyed Mix
Tannor- Golden Retriever CGC
Robyn- German Shepherd CGC
Cats-Thunder, Harley, Miley, Bandit, and Ferah
RIP Boo..Black Lab
"A dog is the only thing on this earth that loves you
more than he loves himself."