London is trying to solve this problem: "A store has a sale where every item has a sale price that is 10% less than the regular price. Write an expression that represents the sale price of an item if the regular price is p dollars."

London said, "To find 10% of a number, I should multiply by 0.10. So the sale price of an item will be 0.10p."

Which statement best describes London's reasoning?

A
London is mostly correct, and just needs to add p.

B
London needs to subtract p from 0.10p.

C
London needs to calculate p minus 0.10p to get the new sale price.

D
London needs to calculate 1.10p to get the new sale price.