Which of the following statements about use-case testing are most accurate? (i)In a use-case diagram an actor represents a type of user. (ii)Use-cases are the most common test basis for unit…

Which of the following statements about use-case testing are most accurate? (i)In a use-case diagram an actor represents a type of user. (ii)Use-cases are the most common test basis for unit testing. (iii)A use-case describes interactions between actors. (iv)An actor is always a human user that interacts with the system. (v)Test cases can be based on use-case scenarios. (vi)Use-case testing will often identify gaps not found by testing individual components.