Rob Has Self Appointed Himself to Enforce the Group Norm

Multiple Choice

Rob has self appointed himself to enforce the group norm.So during the discussion every time Ralph brings up an objection Rob counters what Ralph has to say.Sometimes criticizing Ralph himself.Rob's self appointed role can be seen as

A) discussion enforcer.
B) closed-mindedness.
C) formation of a "mindguard."
D) squelching of dissent.