When I first read this I was confused about the restaurant; since they call it "MD's" I thought it was just one of those classic knockoff McDonald's, but the fact that its a donut restaurant called "Mrs Donut" really threw me
Well, know that I'm rereading this chapter to refresh me on recent events in the manga I understand that it's actually a knockoff Mister Donut, a donut chain restaurant that was (almost) completely converted to Dunkin Donuts in the US. I only realized this because I actually just ate at a Mister Donut for the first time the other day