Well, as always the actual answer is 'whatever you like', but I don't suppose that's particularly helpful.
From a pure profit perspective, Hops are one of the most profitable things you can grow in your greenhouse because they produce daily. Brew those hops into pale ale, and you've got a rather lucrative business. Yes, you can't walk through them, however planning out your area ahead of time can help you maximize the profits. I've written a
guide you can read if you like, going over the particulars.
However, if you're not keen on the idea of having to put in work every day, then there's another solution, but it isn't any of the options you mention. Ancient Fruit. All you need is one seed and a Seed Maker machine and you can propagate it. Once it is fully grown, and producing fruits on a weekly basis, process those fruits through your Seed Maker, plant, and repeat the process until you have a greenhouse full of ancient fruit raking in about a million per season. Getting your first ancient fruit can be a bit tricky, as you can't just purchase them. They've got a small chance of dropping from the bugs in the mines around levels 10-25, or if you run other seeds through the seed maker, there's roughly a half percent chance that instead of getting that seed, you'll get an ancient seed instead.
If you don't want to go through that effort, and just want to know which of the three, then it depends on how you want to process them. If you are just using preserves jars, I'd suggest blueberries, as they triple in value when turned into preserves. If you've got spare kegs, then go with Strawberries, as strawberry wine is more profitable.
Either way you go, don't forget you can plant peach and pomegranate trees around the perimeter of the growing area, rather than directly on it, for even more profits!