It is not possible for the parties to refer to mediation for all kinds of disputes. According to Article 1/2 of the Mediation Law, only private law disputes arising out of matters that the parties may freely dispose of, including those that carry a foreign element, can be subject to mediation. Therefore, the disputes arising out of subject matters related with public policy can not be referred to mediation. For example, spouses may not refer to mediation for divorce; or disputes concerning affiliation of a child to one of his/her parents may not be subject to mediation. Therefore, the correct option is C.