The Solution:
We are asked to identify a literal equation in the given options.
Step 1:
Definition of a literal equation.
A literal equation is an equation with more than one variable.
For example, the formula for the area of a circle as given below:
![A=\pi r^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/lcgfavc89jro4qntamn2b9gfliomu1jwuf.png)
So, the example of a literal equation in the given options is:
![\begin{gathered} ax-by=k \\ \text{ Since it has more than one variable and it has an equality sign.} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4x66bop7m219um9tg7vfnxbg3ix88v7jwq.png)
Therefore, the correct answer is [option C]