types of metering

You're asking a lot of different questions here. First, No, you would not automatically use Option B. Doing a building simulation creates a baseline for M&V. You can use other sources for that and use Option D. Since you have a smaller building you can use Option B. If you are going to rent out spaces and charge them for the energy they use you may want to use submeters if your Utility company lets you. otherwise just have the Utility company put in one meter for the entire building. What is really important here above everything else, If you are going for this credit, is to have a good M& V plan. See the post above by Christopher Schaffner.