Answer:c) Not Necessary, While the team need to ensure that each increment is thoroughly tested, all increments work together and meets the definition of done, it is up to the team to find the best method to achieve this.
The Agile methodology values individuals and interactions over processes and tools. It encourages self-organizing and cross-functional teams to work together and find the best approach to deliver working software incrementally. While it is important to test each increment thoroughly, including non-functional testing, the specific testing strategy is not prescribed. The team can choose the best method to achieve their goals based on their context and needs.