Each piece of candy in a store costs a whole number of cents. Casper has exactly enough money to buy either 12 pieces of red candy, 14 pieces of green candy, 15 pieces of blue candy, or n pieces of purple candy. A piece of purple candy costs 20 cents. What is the smallest possible value of n?<spanclass=′latex−bold′>(A)</span>18<spanclass=′latex−bold′>(B)</span>21<spanclass=′latex−bold′>(C)</span>24<spanclass=′latex−bold′>(D)</span>25<spanclass=′latex−bold′>(E)</span>28