"Back then, we didn't have computers, printers and copy machines. Thus you can get 95% effectiveness in say 1 month opposed to 100% effectiveness in five years. It's actually very simple since you already found all of your research.
The C sizes are just between the A and B number of. Would be a thing or a phrase that represents an option. And will soon be searching ideas of their own ways to implement science into a lot of fun.