++++ ++++ ++++ ++++ ++++ Concept Question ++++ ++++ ++++ ++++ ++++ Which of the following statements is true? 1. The PVD and the PMPE are equivalent 2. The PVD is more general 3. The PMPE applies to any kind of material 4. The stationary character of the potential en- ergy is equivalent to the PVD for elastic ma- terials 1. ++++ Statements (1) and (3) 2. ++++ Statements (1) and (4) 3. ++++ Statements (2) and (3) 4. ++++ Statements (2) and (4) 5. ++++ DKDU The right answer is (4) ++++ .