Answer:
[tex]\large\boxed{5^{-5}=\dfrac{1}{5^5}}[/tex]
Step-by-step explanation:
[tex]\text{Use}\ \dfrac{a^n}{a^m}=a^{n-m}\\\\\dfrac{5^3}{5^8}=5^{3-8}=5^{-5}\qquad\text{use}\ a^{-n}=\dfrac{1}{a^n}\\\\=\dfrac{1}{5^5}[/tex]
Based on the correction of the question in the comment.
[tex]\dfrac{5^5}{5^8}=5^{5-8}=5^{-3}=\dfrac{1}{5^3}[/tex] → A
