In Oracle Database 12c SQL, regarding date/time functions and considering a session where NLS_DATE_FORMAT is set to DD-MON-YYYY SH24:MI:SS:
* C. CURRENT_DATE returns the current date and time as per the session time zone. This is correct as CURRENT_DATE returns the current date and time in the time zone of the current SQL session, as set by the ALTER SESSION command.
* D. SYSDATE and CURRENT_DATE return the current date and time set for the operating system of the database server. This is partially correct. SYSDATE returns the current date and time from the operating system of the database server. However, CURRENT_DATE returns the date and time set for the client's operating system environment, adjusted to the session time zone.
Options A, B, E, and F are incorrect based on Oracle's documentation:
* A is incorrect because SYSDATE is independent of the NLS_DATE_FORMAT setting.
* B is incorrect because CURRENT_TIMESTAMP includes time zone information, which can differ from CURRENT_DATE.
* E is incorrect because CURRENT_TIMESTAMP differs from SYSDATE by including fractional seconds and time zone.
* F is incorrect as SYSDATE can be queried in any SELECT statement, not just from DUAL.