Which of the following is true of JUnit testing when the unit under test is a single method?
1) JUnit testing can prove the correctness of the method body
2) JUnit testing is generally considered an expensive waste of time in industry
3) A single JUnit test case can show the presence of a defect in the method body
4) A single JUnit test case can show the absence of defects in the method body
5) None of the above are true