Which of the following statements is correct for the function A(I)=- 1/2x^2 +9x, where A(l) is the area of a rectangle of length l in square meters? a. The area has a minimum value of 40 1/2 square meters. 2. The area equals 18 square meters when the length is 0 meters. C. The area equals 40 1/2 square meters when the length is 9 meters. d. The area has a maximum value of 9 square meters.​