What is the location of the ADR base?

The environmental variable oracle_Base is set to /u01/app/oracle and oracle_home is set to
/u01/app/oracle/product/12.1.0/db 1. You want to check the diagnostic files created as part
of the Automatic Diagnostic Repository (ADR). Examine the initialization parameters set in
your database. What is the location of the ADR base?

A.
It is set to/u01/app/oracle/product:/12.1.0/db_1/log.

B.
It is set to /u01/app/oracle/admin/enl2r&p/adump.

C.
It is set to /u01/app/oracle.

D.
It is set to /u01/app/oracle/flash_recovery_area.