A pet store regularly sells pet food at a discount of 10 percent to 30 percent from the manufacturer’s suggested retail price. If during a sale, the store discounts an additional 20 percent from the discount price, what would be the lowest possible price of a container of pet food that had a manufacturer’s suggested retail price o f $ 30.00?
Choose the correct answer:
A) $ 10.00
B) $ 11.20
C) $ 14.40
D) $ 16.80
E) $ 18.00

Rationale: "for retail price = $ 30 first maximum discounted price = 30 - 30 % of 30 = 30 - 9 = 21 price after additional discount of 20 % = 21 - 20 % of 21 = 21 - 4.2 = 16.8 answer : option d"
Answer: D