Ratio and Proportion

Concept:The given expression $\frac{p}{q} = \frac{r}{s}$ is the fundamental equality of two ratios, not a named transformation.Explanation:In ratio and proportion, terms like Componendo, Alternendo, and Subtrahendo refer to specific operations on a proportion (e.g., $\frac{a}{b} = \frac{c}{d}$).For example, Componendo gives $\frac{a+b}{b} = \frac{c+d}{d}$. Alternendo gives $\frac{a}{c} = \frac{b}{d}$.Here, no such transformation is applied; the statement simply repeats the equality of two ratios.Therefore, none of the named options correctly describes this process.Answer:D. none of these