i have 1 ldap sever (name=ldap.a.com), 2 mta server (mta01.a.com and mta02.a.com), 1 mailbox server (mailbox.a.com)
when installing zimbra-store, there is a option "smtp host"

Option Nro1

smtp host: mta01.a.com mta02.a.com

or

Option Nro1

smtp host: mta01.a.com, mta02.a.com

what option is the best