To determine when your procedure was last compiled, you should query the USER_OBJECTS table.
Let's analyze each option to understand why the correct answer is C:
Option A) USER_PROCEDURES - This option is incorrect because the USER_PROCEDURES table does not provide information about when a procedure was last compiled. It contains information about procedures owned by the current user, but not the compilation timestamp.
Option B) USER_PROCS - This option is incorrect because there is no standard Oracle table named USER_PROCS. It is not a valid table in the Oracle database.
Option C) USER_OBJECTS - This option is correct because the USER_OBJECTS table contains information about all objects owned by the current user, including procedures. It includes a LAST_DDL_TIME column that represents the timestamp of the last DDL (Data Definition Language) operation performed on the object, which includes the compilation of a procedure.
Option D) USER_PLSQL_UNITS - This option is incorrect because the USER_PLSQL_UNITS table stores information about PL/SQL units, such as packages, functions, and procedures. However, it does not specifically provide information about when a procedure was last compiled.
The correct answer is C) USER_OBJECTS. This table should be queried to determine when your procedure was last compiled because it includes the necessary information in the LAST_DDL_TIME column.