A biologist studied the populations of white-sided jackrabbits and black-tailed jackrabbits over a 5-year period. The biologist modeled the populations, in thousands, with the following polynomials where x is time, in years. White-sided jackrabbits: 9.7x2 – 0.8x + 2.3 Black-tailed jackrabbits: -1.1x2 + 7.7x + 5.4 What polynomial models the total number of white-sided and black-tailed jackrabbits? A. -8.6x2 + 6.9x - 7.7 B. 8.6x2 - 6.9x + 7.7 C. 8.6x2 + 6.9x + 7.7 D. 8.6x2 - 6.9x – 7.7