Ichabod runs a clothing store in London. He recently purchased 1000 dress shirts that had a manufacturer's list price of $45. On each shirt, there was a trade discount of 10%, 8%, and 6% from the manufacturer. Ichabod's store has operating expenses that are 35% of the selling price, and the rate of markup is 60% on the selling price. What was the cost per shirt to the store?
a) $16.20
b) $16.40
c) $16.60
d) $16.80