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Don't recall if it applies to all routing protocols, but believe many will use IP Prec 6 or CS6 which would, if recognized and treated, should take precedence over all user type traffic, even traffic like VoIP which is generally marked IP Prec 5 or DSCP EF. (NB: reason for this, if the network doesn't have the correct information, it's possible all user type traffic will be negatively impacted.)
What I've just described is for L3 packet ToS. Switch's using L2 CoS, should generally map IP Prec or DSCP CS into the same CoS values, and if they do, routing information should also be given priority over all user type traffic.
NB: remember, whether L3 ToS or L2 CoS, it's up to the devices whether they will treat traffic differently and how such treatment will be done. I mention this because an exam answer may not correspond to "real world".
