The task involves rewriting exponential equations into their equivalent logarithmic form. Let's analyze each exponential equation and determine its logarithmic counterpart.

1. Exponential Equation: $8 = 2^3$
   Logarithmic Form: The logarithmic equivalent is $\log_2 8 = 3$.

2. Exponential Equation: $625 = 5^x$
   Logarithmic Form: The logarithmic equivalent is $\log_5 625 = x$.

3. Exponential Equation: $9^r = s$
   Logarithmic Form: The logarithmic equivalent is $\log_9 s = r$.

Now you can match these logarithmic forms with the choices provided in the image.

Would you like a breakdown of how logarithmic conversions are derived? Here are some questions to deepen understanding:

1. What are the key rules for converting between exponential and logarithmic forms?
2. How does the base of the logarithm relate to the base in the exponential equation?
3. Why is it important to clearly identify the input and result when solving for a logarithm?
4. Can you try rewriting an exponential equation with a fraction (e.g., $4^{1/2} = 2$) into logarithmic form?
5. How do logarithmic equations apply to real-world problems, like calculating growth or decay?

Tip: Always remember the general relationship: $a^b = c$ is equivalent to $\log_a c = b$.