Can the graph of a standard exponential function: $y=b^x$, where $b>0$ and $b\ne 1$, ever have an $x$-intercept?

• A. Only when $b>1$ will the graph cross the x-axis on the right side of the plane
• B. Yes, every exponential function must cross the $x$-axis at least once because exponents can be negative
• C. Yes, for certain bases, the graph will cross the $x$-axis when $x$ is a sufficiently large negative number
• D. No, the $x$-axis, $y=0$, is a horizontal asymptote and the graph will approach the asymptote but it will never reach it

Answer: (D)