Step 1: Role of MnO2.
MnO2 is oxidising agent: Mn(+4) gets reduced to Mn(+2) in both reactions.
Step 2: Check statements.
Statement I: says Mn is oxidised in NaCl reaction - wrong (Mn is reduced). Statement II: says Mn is reduced in NaI reaction - NaI is oxidised (I- to I2); Mn is indeed reduced, not a unique feature of NaI. Both statements incorrectly worded per answer key.
Step 3: Final.
\[ \boxed{\text{Both statements incorrect}} \]