A manufacturer has been selling 1,200 television sets a week at $400 each. A market survey indicates that for each $30 rebate offered to the buyer, the number of sets sold will increase by 60 per week. Find the demand function. A p(x) = - 0.5x + 1,000 B p(x) = 0.5x + 1,000 C p(x) = 0.5x + 600 D p(x) = - 0.5x + 400,5 E p(x) = 0.5x