Thanks for reporting this. It appears there’s some filesystem issue with this question.
I’ve notified the lab’s team and requested for early resolution of this question in the lab.
The error “ln: failed to create hard link ‘/home/bob/hlink’ => ‘/tmp/hlink’: Invalid cross-device link” occurs when trying to create a hard link between files that reside on different filesystems or partitions. Hard links can only be created within the same filesystem
So, the team has updated the path. It’s no longer /tmp/; it’s now /opt/.