Consider the following statements with reference to NC machines:
1. Both closed-loop and open-loop systems are used.
2. Papers, tapes, floppy tapes and cassettes are used for data storage.
3. Digitizers may be used as interactive input devices.
4. Post-processor is an item of hardware.
Which of the above statements are correct?1
1, 2 and 4
2
1, 3 and 4
3
2, 3 and 4
4
1, 2 and 3