* The question is about selecting the correct test values for x based on equivalence partitioning.
Equivalence partitioning is a software test design technique that divides the input data of a software unit into partitions of equivalent data from which test cases can be derived. In this case, the given equivalence classes are:
* (x \leq -100)
* (-100 < x < 100)
* (100 \leq x < 1000)
* (x \geq 1000)
Option D provides a value from each of these partitions:
* For (x \leq -100), it gives -1000.
* For (-100 < x < 100), it gives -100 and 100.
* For (100 \leq x < 1000), it gives 500.
* For (x \geq 1000), it gives 1500.
So, option D covers all four given equivalence classes with appropriate values.
References: ISTQB Certified Tester Foundation Level (CTFL) v4.0 documents available at ISTQB and ASTQB.
* 1: ISTQB Foundation Level Syllabus 2018, Version 4.0, p. 38
* 2: ISTQB Foundation Level Syllabus 2018, Version 4.0, p. 39
* : ISTQB Foundation Level Syllabus 2018, Version 4.0, p. 40