A test condition is an item or event of a component or system that can be verified by one or more test cases. A test condition can be derived from various sources of information, such as requirements, specifications, design documents, use cases, user stories, etc. A test condition can also be based on various aspects of a component or system, such as functionality, usability, performance, reliability, security, etc.
The other statements are not true about test conditions because they describe different concepts related to testing. For example:
B. The grouping of a composite set of test cases which, when tested as a whole, reveal a positive or negative result: This statement describes a test suite, which is a collection of test cases that are intended to be executed together to achieve a specific test objective or goal.
C. A testable component derived from business requirements: This statement describes a test basis, which is the source of information or data that provides the basis for designing and executing test cases.
D. Applies to software testing only: This statement is false because test conditions can apply to any type of testing, not just software testing. Test conditions can also be used for testing hardware, systems, processes, etc.
You can find more information about test conditions in [A Study Guide to the ISTQB® Foundation Level 2018 Syllabus], Chapter 4, Section 4.1.
