The price of commodity X increases by 30 cents every year, while the price of commodity Y increases by 20 cents every year. If in 2001, the price of commodity X was $4.20 and the price of commodity Y was $4.40, in which year will commodity X cost 40 cents more than the commodity Y?  Choose the most appropriate option.
A) 2007  B) 2008  C) 2009  D) 2010  E) 2011

Rationale: "the cost of commodity x increases by 10 cents per year relative to commodity y . the price of x must gain 20 + 40 = 60 cents on commodity y , which will take 6 years . the answer is a ."
Answer: A