The ________ command gives Linux users the ability to perform administrative duties, which require a separate password for each user

Which of the following cryptographic algorithms is irreversible?

A. RC4 B. SHA-256 C. DES D. AES

If you press the ____ key while drawing a selection, Photoshop creates the marquee from the center.

a. TAB b. ALT c. C d. none of the above