B. r = fractional growth rate for the quantity (or decay rate) C. Qo = value of the quantity at time t D. t = time Explain how the function is used for exponential growth and decay. Choose the correct answer below. Select all that apply. A. The function is used for exponential growth if r 0. C. The function is used for exponential growth if r > 0. D. The function is used for exponential decay if r