The correct option is C MnO2 acts as an oxidising agent while HCl acts as an reducing agent
MnO2+4HCl=MnCl2+Cl2+2H2O
Writing the oxidation numbers on various atoms,
+4Mn−2O2++14H−1Cl=+2Mn−1Cl2+0Cl2++12H2−2O
Oxidation number of Mn from +4 to +2 i.e., decrease in oxidation number. MnO2 is thus reduced. It acts as an oxidising agent. Oxidation number of Cl changes from −1 to 0, i.e., increase in oxidation number. HCl is thus oxidised. It acts as a reducing agent.