Caden buys 3.9 pounds of grapes that cost $1.80 per pound. Which expression can be used to find the total cost of the grapes?
(3+0.9) 1+ (3 +0.9) x 8
(3 x 0.9) 1+(3 x 0.9) x 8
(3 x 0.9) 1+ (3 x 0.9) x0.80
(3 +0.9) 1 + (3+09)x 0.80