15. What is the area of the rectangle given the length of (x+3) cm and width of (x + 1) cm? + + a. (x2 + 4x + 4) cm2 C. (x2 + 3x + 3) cm2 b. (x2 + 3x + 4) cm2 d. (x2 + 4x + 3) cm?​