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) x 1 + (3 + 0.9) x 8
(3 x 0.9) x 1 + (3 x 0.9) x 8
(3 x 0.9) x 1 + (3 x 0.9) x0.80
(3+0.9)1+(3+0.9) x0.80