(c) 4, 2, 1
Balancing: MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂. Mn=1, O=2, H=4, Cl=4 on both sides. So x=4, y=2, z=1.
Balance each element: 4 HCl provides 4 Cl atoms — 2 go to MnCl₂ and 2 form 1 Cl₂; 4 H atoms form 2 H₂O; 2 O atoms (from MnO₂) form 2 H₂O. All atoms balance. Examiners expect the correct option with brief verification.