1. C
2. D
3. /etc/security/pwquality.conf
4. 077
5. Change the DIR_MODE setting to DIR_MODE=0700.
6. To forget about using complex passwords that expire on a regular basis, and to instead use a long, easy-to-remember passphrase that never expires.
7. B
8. D
9. D
10. A, D
11. C
12. B
13. B
14. C
15. D