A question from Cambridge CD

[harbinger]

M: I cannot believe how much I spend for textbooks these days. Everything costs more
WM: I know, the price of hardback books has double in the last three years.

What does the woman mean?

A. Two years ago hardback books cost a third as much as know
B. The cost of hardback books has gone up twice in the last three years
C. Hardback books cost twice as much as before
D The cost of hardback books goes up two or three times a year


I pick B but the answer is C. What is the difference between B and C?

Thanks

[vuhl74]

Originally posted by harbinger

M: I cannot believe how much I spend for textbooks these days. Everything costs more
WM: I know, the price of hardback books has double in the last three years.

What does the woman mean?

A. Two years ago hardback books cost a third as much as know
B. The cost of hardback books has gone up twice in the last three years
C. Hardback books cost twice as much as before
D The cost of hardback books goes up two or three times a year

I pick B but the answer is C. What is the difference between B and C?

C is obviously correct. B is incorrect as "The cost of hardback books has gone up twice in the last three years" means the book price has been adjusted 2 times during the last three years. Like the initial price is 10$, the it was increased to 12$ [first time] and then again to 14$ [second time].