b) work 5 days at-home
c) work 4 days in-office (shortened work week)
The only ground I'm willing to give on the topic is that it's not for everyone. As mentioned, it's a choice. If I mandate my employees to one way, I'm equally wrong. However, I wouldn't hire a single individual who couldn't be coached remotely or learn remote and that's because I'm not going to bring someone into a situation they can't win.
If you live an hour from the office, the commute for a 4 day work week is 8 hours total. So you could frame the choice between B and C as spending 8 hours in the comfort of your own home being productive vs spending 8 hours in traffic.
If you live less than an hour from the office, C becomes more appealing because you can organize a 3-day weekend (camping trip, visiting another city, whatever) every week.