Final answer:
The correct statement regarding test estimation approaches is that the expert-based approach involves test managers estimating the expected testing effort, utilizing their experience and knowledge.
Step-by-step explanation:
Among the test estimation approaches mentioned, statement C is CORRECT: With the expert-based approach, the test managers responsible for the different testing activities predict the expected testing effort. This involves using the knowledge and experience of professionals who are familiar with the complexities of the application and the testing process. They often have a good initial understanding that helps in creating more accurate estimations, verifying assumptions, and performing necessary adjustments. Furthermore, experts are able to provide insight into the different aspects that contribute to the testing effort, such as risk factors, technology challenges, past experiences, and resource availability.
It is also important to note that a metrics-based approach involves using historical data and statistical methods from past projects to estimate future efforts. This may include analysis of the past performance of the testing team, the complexity of previous projects, the number of defects discovered, or the time taken to perform certain testing activities.