The following rules determine the annual bonus to be paid to a salesman of a...

This answer is correct because equivalence partitioning is a test design technique that divides the input domain of a system or component into partitions of equivalent data, such that each partition is expected to produce the same output or behavior. Equivalence partitioning aims to reduce the number of test cases by selecting one representative value from each partition. In this case, the input domain of the TAS can be divided into four partitions based on the bonus rules: less than 50k€, between 50k€ and 80k€, between 80k€ and 120k€, and more than 120k€. The test cases in the answer belong to the same partition, which is between 80k€ and 120k€, and they are expected to produce the same output, which is a bonus of 15%. References: ISTQB Glossary of Testing Terms v4.0, ISTQB Foundation Level Syllabus v4.0, Section 2.3.2.1