What is on a plain cheese pizza? Not only cheese I hope? In the pictures it looks like there is tomato sauce but I have never particularly ordered a 'plain cheese pizza' in the US; I only ordered with toppings.
I know there are regional differences in “pizza expectations”, but typically a cheese pizza is crust->tomato sauce->cheese. A margherita pizza would add sliced or diced fresh tomatoes and chopped fresh basil leaves on top of that stack.