NT,what's the pathname for create directory?

[ligang]

In WinNT , Oracle8.1.7,

If I want to create a logical directory d1 point to c:\oracle\tmp

which one I should use:
1. CREATE OR REPLACE DIRECTORY d1 AS 'c:\oracle\tmp';
2. CREATE OR REPLACE DIRECTORY d1 AS 'c:\oracle\tmp\';
3. CREATE OR REPLACE DIRECTORY d1 AS 'c:/oracle/tmp';
4. CREATE OR REPLACE DIRECTORY d1 AS 'c:/oracle/tmp/';

[ligang]

Only 1 is working . I tried