Exponential decay is described as when the quantity of any entity decreases in accordance with the entity's present value. For example - if a group of population decreases and the decreasing rate value is proportional to the size of the population.
So, the correct options are :
A. The domain is all real numbers. (the function is always defined for real values)
D. The base must be less than 1 and greater than 0.
E. The function has a constant multiplicative rate of change.