Which of the following statements about error guessing is true?

This answer is correct because error guessing is a test design technique where the experience and intuition of the tester are used to anticipate where errors, defects and failures have occurred or are likely to occur, and to design test cases to expose them. Error guessing can be based on factors such as the complexity of the system or component, the known or suspected weaknesses of the system or component, the previous history of defects, or the common types of errors in the domain or technology. Error guessing can be used as a complementary technique to other more systematic or formal techniques, or when there is insufficient information or time to apply them. References: ISTQB Glossary of Testing Terms v4.0, ISTQB Foundation Level Syllabus v4.0, Section 2.3.2.5