Dimethyl sulfoxide (DMSO) reductase catalyzes the reduction of dimethyl sulfoxide (DMSO) to dimethyl sulfide (DMS) during anaerobic respiration; it can also use trimethylamine N-oxide (TMAO) as terminal electron acceptor. Subunit C is proposed to be a membrane anchoring subunit. Probable multiprotein complex that likely consists of DmsA, DmsB and DmsC. By anaerobic conditions. Its expression is under the control of DmsR. Belongs to the NrfD family.