Assertion: In the reaction between potassium permanganate and potassium iodide, permanganate ions act as an oxidising agent.

Reason: The oxidation state of manganese changes from +2 to +7 during the reaction.

1.  Both assertion and reason are true and the reason is the correct explanation of assertion.

2.  Both assertion and reason are true and the reason is not the correct explanation of assertion.

3.  Assertion is true but the reason is false.

4.  Assertion is false but the reason is true.

Hint: Mn oxidation state in KMnO4 is +7.

The reaction is as follows:
$10\mathrm{KI}+2\mathrm{K}\stackrel{+7}{\mathrm{M}}{\mathrm{nO}}_{4}+8{\mathrm{H}}_{2}{\mathrm{SO}}_{4}\to 2\stackrel{+2}{\mathrm{M}}{\mathrm{nSO}}_{4}+6{\mathrm{K}}_{2}{\mathrm{SO}}_{4}+8{\mathrm{H}}_{2}\mathrm{O}+5{\mathrm{I}}_{2}$

The oxidation state of Mn decreases from +7 to +2.

Hence, the Assertion is true but the reason is false.