The manufacturer of a new product developed the following expression to predict the monthly profit, in thousands of dollars, from sales of t product when it is sold at a unit price of x dollars. -0.5x2 + 221 – 224 what is represented by the zero(s) of the expression? a. the unit price(s) when the profit is equal to 0 b. the unit price(s) when profit is greatest c. the profit when the unit price is equal to 0 od. the profit when the unit price is greatest reset next