Solution
The rule for negative exponent a^-n = 1/a^n, why it does not apply when a = 0.
when a = 0
[tex]a^{-n}=\frac{1}{a^n}[/tex][tex]\begin{gathered} a^{-n}=0^{-n}=0 \\ \frac{1}{a^n}=\frac{1}{0^n}=\infty,\text{but you cannot divide by zero} \end{gathered}[/tex]
Hence the correct answer is Option A
