You can only save one

Teen Titans but only the Go version

JLU, no contest.

JLU
Young Justice was quite literally never good

I save Teen Titans.

Justice League was the best out of them

Though I will say Teen Titans is one of the best non DCAU DC Cartoons, alongside the Fleischer Superman Cartoons and Batman the Brave and the Bold

But JLU doesn't need saving. It ended in a really decent note, closed all the storylines and even gave a cool ending to Batman Beyond. Learn to appreciate good endings.

So I'd pick Teen Titans by default.

I hate to say it but Young Justice. That's not to say JL sucks, but Bruce Timm and Paul Dini were a mistake in the long run of DC comics because they are the reason why Batwank exist.

Teen Titans easily

JLU>TT>YJ
Even before YJ got renewed and became crap it was a lot weaker than the other two shows. TT is good but I still prefer JLU.
If you replace YJ with the Brave and the Bold it's a bit of a harder decision. JLU is still on top for me but I think Brave beats out TT.

>Teen Titans
they are self-aware and funny, some really good episodes