Option A is what I would recommend - very, very strongly. You'll have a fully functioning Micros server, the only real restriction is that it will run in demo mode, so all sales will post to the same business date and you can't run live credit cards.
If you decide to go with option B use an ODBC connection in your .net application. You don't need drivers or connection strings that way. Also, make it a self contained executable that doesn't use any external dll's or config files. You want something that you can just copy to the server and run without an installation package. And run it when the restaurant is closed and after backing up the database.
The reason I'm annoyed is that you are new to working with Micros but seem reluctant to install it and know the product you're trying to write an application for. I've been working on this system for over 15 years but still have 8 images with various versions of 3700 so I can write and test my products on the correct platform. I've also a ton of substandard, and a few rather questionable, 3rd party apps written by people who thought they could use basic development knowledge without understanding the product they're connecting to. The data in Micros is confusing. There are 877 tables, 612 views and 35 global temp tables. You have to know what you're looking at and how everything interacts. It's very, very easy to pull incorrect information.