Which of the following statements are true for ultrasonic welding? 1. Productivity of ultrasonic welding is high 2. Thin pieces can be welded to thicker pieces by ultrasonic welding 3. Ultrasonic welds contain foreign inclusions 4. Post cleaning of welds is necessary in ultrasonic welding 5. Preparation required for ultrasonic welding process is very little

• A. (1), (2) and (4)
• B. (2), (3) and (4)
• C. (1), (3) and (5)
• D. (1), (2) and (5)