A and C
I've had multiple KI229 slaved RMI failures. Sometimes one or the other needle (or both) stops working, or the OBS stops rotating. But on the slaved HSI next to it, all works fine... once it was an inverter, or maybe changing it disturbed a connector?
Once I cancelled a departure because both slaved instruments were found to be duff; it turned out that a circuit breaker had been kicked (by me) when getting in...
But most important thing I think is to finally walk around, check the towbar isn't attached, luggage door not open, etc. I might have a little bracket welded to the towbar and clip the ignition keys to it at the start of the checks.