Mooredog: I believe that TDA Rule 29 is applicable here. Even though Rule 29 is titled "Verbal Declarations", the second sentence says: "Action out of turn will be binding if the action to that player has not changed". In our example, I believe that Player C should be able to retract his call, since the raise by Player B certainly changed the action.
That said, there are many, many card rooms that claim to "follow TDA Rules", but for just as many reasons as there are such rooms, have 'house rules' that differ. In some cases, it may be due to requirements of the local gaming agency. In others it may be due to "local custom". Regardless of the reason, the important part is that the rules be known and the application be consistent.
Hope this helps!!