They should get a D or something, not an F. Their options are not overly plant-based friendly (can I just say "vegan friendly"?), but after researching their menu you are able to piece together vegan options from what they give you.
It should be noted, however, that that option is not plant-based by default. They make it with regular egg-based mayonnaise and you have to request it taken off.
They also have a delicious Masala burger they introduced for a limited time.
I am not vegetarian or vegan, but will happily sub a Beyond/Impossible patty for a meat patty, I just resent it when that's an upcharge (I have a whole rant on that).
The Masala burger is not a meat substitute patty, it's a vegetable patty that doesn't pretend to be anything else. I think it also has paneer and other toppings. It's delicious, it's a decent size, and it's $6.
As someone who will happily eat a meat burger. The Masala burger is just a plain good burger that happens to be vegetarian (maybe Vegan).