Your friend really wants to buy the newest cell phone which will cost him $750. He gets a job detailing cars and SUVs and plans to save all the money he earns. If he gets paid $55 to detail a car and $70 to detail an SUV, what linear inequality can be used to determine how many of each he must detail in order to earn at least $750?
A: 55c+70x [tex]\leq[/tex] 750
B: 55c+70x > 750
C: 55c+70x [tex]\geq[/tex] 750
D: 55c+70x < 750