The time to assemble a television at a factory is 2.5 hours. A stereo only requires 1.5 hours. The factory workers can supply at least 580 and at most 750 hours of assembly time each week. The factory is producing 3 times as many televisions as stereos. What is the inequality?
A) 580=<4x=<750
B) 580<4<750
C)580=<9=<750
D)580<4<750