In a store, the total price for 20 shirts is $360 and the total price for 45 sweaters is $900. By how much does the average (arithmetic mean) price of a sweater exceed that of a shirt in this store?	Choose the correct choice from the following answers:
A) $ 1  B) $ 2  C) $ 3  D) $ 4  E) $ 5

Rationale: "the average price of a shirt is : $ 360 / 20 = $ 18 . the average price of a sweater is : $ 900 / 45 = $ 20 . the difference in price is : $ 20 - $ 18 = $ 2 . the answer is b ."
Answer: B