the system of equations models the price per share, y, for two stocks overtime, x. which represents the viable solution to the system? -y<= 3x+4-3x-3y<=-9. A. all real number values of x and y.
B. all real number values, with x >=0
C. all real number values, with y >=0
D. all real number values, with x >=0 and y>=0​