^^^That^^^
If you're dressed as female and go into the women's room nobody knows for sure if you are TG or simply a masculine-looking woman.
If you're dressed as female and go into the men's room everyone knows that you're TG.
Be safe.
That said, I've used hundreds of ladies rooms and, at 6'2", I stand out. I have never had anyone say a single negative thing to me or in my earshot.