Designing Kitchens and Bathrooms - Measuring for a Faucet

This may seem like a simple question but it has me a little confused and I want to be certain I understand it before I carry through with a project.

I am going to replace my bathroom sink. It's a countertop sink that sets on a vanity. I'm keeping the vanity - just replacing the countertop sink.

In looking over the options (Corian, etc), the instructions ask for a measurement for cutting out the faucet holes. The options are: None, One hole, 4-inch and 8-inch.

How do I measure the faucet holes correctly? When I look underneath the sink there's three holes for the faucet. Do I measure the distance from the centers of the two outer holes? Is the center hole measurement just factored in once they have the measurements from the two outer holes?

I'm a little confused and want to make sure the holes are drilled correctly. Could anyone explain this to me a little more clearly? Thank you!

You are correct on the proper way to measure the distance between the holes. I would, for clarification purposes, also add that the faucet has a pop-up drain. This way they will install that hole in case they normally don't. Good luck with your project.

Thanks for the confirmation as well as the good idea of mentioning the pop-up drain! I appreciate your quick response too!