I voted black, but whatever you do just don't chose tort and you'll be good.
Just my opinion I guess, but tort looks butt ugly in by far most combination.
I honestly can't figure out why it is people insist using a tort pick guard even when it clearly throws off the whole balance of their bass's overall look and color scheme.
In my opinion there's something disgustingly sultry and cloying over tort pick guards, you know like the smell, look and feel of a small bar where the customers smoke too much and the owners clean up too little.
I guess some find that appealing in sort of a charming and cozy way though, might be the same type of people tort pick guards appeal to?