I think the one from /etc/fstab. The manual of tune2fs says:
Set or clear the indicated default mount options in the filesystem.
I take this to mean that if you have "defaults" in /etc/fstab, then the FS option can specify what is the default for that particular file system. I would think the default would get overridden by an explicit mount option from /etc/fstab though.
But, that's easy to check. Just set the options on the FS level and/or fstab, mount and check dmesg to see what really happened.