Each week, a company can sell x units of it's product at price of p dollars each, where$($p $=600-5$x$).$ The weekly revenue of the company will then be:$($R$($x$)=600$x $-5$x$7).$ What price per unit should the company charge to obtain a weekly revenue of$$18000?$ a$.$ $$60/$unitO b$.$ $$70/$unit c$.$ $$350/$unit d$.$ $$300/$unit