Modify TNSNAMES.ORA file to connect to an Oracle Database

I would like to modify TNSNAMES.ORA file to connect to an ORACLE Database and I noticed that on my PC there are 3 different files with name TNSNAMES.ORA files. Which of these three should I modify in order to make connection D:\app\XXX\product\11.2.0\client_32\network\admin E:\app\XXX\product\11.2.0\client_64\network\admin D:\app\XXX\product\11.2.0\client_1\network\admin