Which of the following statements about Use Case Testing is FALSE?
A. Use case generally has a mainstream scenario and may have many alternate or exceptional scenarios.
B. A use case can be defined at the abstract level, detached from the implementation, or at the system level, describing a set of executed functions
C. Use case testing does not find defects caused by interaction of different components
D. Each use case has preconditions which need to be met for the use case to work successfully