Option A is my pick - isn’t as crowded and the employees can keep an eye on entire store including the WC and possible outside customers. I agree with fellow Nostrs that less people want to sit next to the door - is it possible to add a 2nd door if you live near in the cold? 
Biggest problem with option B is zero space for a customer line, I can’t see where the employee would get into the work space, and I’m guessing the machines would prevent any way to view the customers from the work area.