What is a percent of b divided by b percent of a?

Answer: Option C

$$\begin{array}{rl}& a\text{percent}\text{of}b\\ & =\frac{a}{100}\times b=\frac{ab}{100}\\ & b\text{percent}\text{of}a\\ & =\frac{b}{100}\times a=\frac{ab}{100}\\ & \text{on}\text{division}\text{we}\text{get}1\end{array}$$