Which of the following groups of amounts falls into three different equivalence classes for customs duty calculations?

Equivalence class testing is a design technique used in software testing that divides input data into equivalent partitions or classes where the system's behavior is expected to be the same. In the context of customs duty calculations, different ranges of amounts may fall into different equivalence classes, each potentially attracting different rates of duty.

The correct answer is determined by identifying the amounts that fall into three distinct equivalence classes. In option C, the amounts are $2,000, $8,000, and $20,000. These amounts are likely to fall into different duty brackets based on the customs regulations. For instance, $2,000 might be considered a lower value that might not attract any duty or might attract a minimal rate, $8,000 may hit a mid-range bracket with a different applicable rate, and $20,000 generally might fall into a higher duty category.

The variations among these amounts suggest that they would likely be treated differently under customs duty rules, as they are spread across a wider range, promoting the likelihood of them falling into distinct classes. This fulfills the requirement of the question, showcasing their categorization into different equivalence classes.

In contrast, the other options have amounts that are either too close together or fall within similar ranges that