4. Which one of the following is the correct sign diagram for the function y = 3) ? O. (x + 1)(x 1)(x I - 3 # 1 1 1 y-0+ 0 0+ . O. . I -3 -1 1 +0 0 0 + I 1 3 y +0 0+0- I 1 1 3 y0+0+0- . -3-1