in 2006, the cost of mailing a letter first class in the United States was $0.39 for the first ounce and $0.24 for each additional ounce.
Which expression shows the cost of mailing a 3-ounce letter in 2006?
A. $0.39 + $0.24
B. $0.39 + 2 ($0.23)
C. 3($0.39 + $0.24)
D. 3 ($0.39) + 2($0.24)