A biology student studied the population growth of two species of frogs over a ten year period. The following polynomial model the results where x is the time in years. Which polynomial models the total number of frogs? Species A: 7x^6 + 3x^3 + 3
Species B: -5x^6 + 9 + 5x^3

A. 2x^6 + 8x^3 - 6
B. -2x^6 + 16x^3 + 8
C. -2x^6 + 16x^3 + 12
D. 2x^6 + 8x^3 + 12