Postfix certificate to connect to Google's SMTP service

Hello

I am trying to connect Postfix to Google's SMTP service and from the instructions there is a setting:

Code:

smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

On that folder i have:

Code:

ca-bundle.crt  ca-bundle.trust.crt  cacert.pem

and i don't know which one to use....

Any ideas?

Thank you