Find the percentage decrease in income from 2001 to 2002.

Answer: Option C

$$\begin{array}{rl}& 2001:\frac{\text{I}}{\text{E}}=\frac{1}{1}=\frac{4}{4}\\ & 2002:\frac{\text{I}}{\text{E}}=\frac{75}{100}=\frac{3}{4}\\ & \text{Income}\%=\frac{4-3}{4}\times 100=25\%\end{array}$$