The answer is A, because if b is equal to one then no matter what x is the answer on the y-axis would be one, since one to any power is one. If b is less than one, for example 0.5, then the result will get smaller as x increases. It would go 0.5^(1), then 0.5^(2)=0.25, and continue to get smaller, therefore getting closer to the x-axis.