Which of the Following Statements Is True About Testing Object-Oriented

Which of the following statements is true about testing object-oriented systems?

A) testing can be minimized since we are reusing parts of systems that have been tested before
B) testing should be designed to prove there are no errors in the system
C) testing is more important than it was in systems developed before object-oriented development
D) encapsulation makes testing easier
E) most testing techniques have been developed to support object-oriented development