A typical objective of testing is to ensure that:

This answer is correct because a typical objective of testing is to ensure that a software has been tested using a combination of test techniques, such as black-box, white-box, or experience-based techniques, that are appropriate for the test objectives, test levels, and test types. Testing using a combination of test techniques can increase the effectiveness and efficiency of testing, as different techniques can target different aspects of the software quality, such as functionality, usability, performance, security, reliability, etc. Testing using a combination of test techniques can also reduce the risk of missing defects that could be detected by one technique but not by another. References: ISTQB Foundation Level Syllabus v4.0, Section 2.3.1.1, Section 2.3.2