Which of the following statements refers to good testing practice to be applied regardless of the chosen software development model?

The principle of "early testing" is a fundamental concept in software testing that applies universally, regardless of the software development lifecycle model. Involving testers in the review of work products, such as requirements and design documents, as early as possible helps to identify defects before code is even written. Finding and fixing defects at this early stage is significantly cheaper and more efficient than finding them later in the development cycle. This practice improves the quality of the work products and prevents defect propagation into the final product.

A. Writing executable tests before code is a practice specific to methodologies like Test-Driven Development (TDD), which is not applied in all models.
B. A strict sequential handoff between test levels, where one's exit criteria feed the next's entry criteria, is characteristic of sequential models, not all models.
C. Test objectives are distinct for each test level (e.g., component testing focuses on code units, while system testing focuses on end-to-end behavior).

ISTQB® Certified Tester Foundation Level Syllabus v4.0, Section 1.1.3, Testing Principle 1, "Testing activities should start as early as possible in the software development lifecycle... Early testing... helps to reduce the cost of changes".

ISTQB® Certified Tester Foundation Level Syllabus v4.0, Section 3.2.2, "Testers can contribute significantly to reviews... by bringing a testing perspective... This early involvement... is a key factor for the success of the project".

ISTQB® Certified Tester Foundation Level Syllabus v4.0, Section 2.2.1, describes how test objectives differ across test levels.