The price of a first-class stamp in 1957 was 3 cents, and it is 41 cents in 2007. From this we know that

the money price of first-class stamps increased from 1957 to 2007 but the absolute price of first-class stamps stayed constant.both the relative and the absolute price of first-class stamps increased from 1957 to 2007.the money price of first-class stamps increased from 1957 to 2007 and the relative price of first-class stamps decreased.the money price of first-class stamps increased from 1957 to 2007, but we can't tell if the relative price of first-class stamps increased or decreased without more information.