Assertion: Among halogens, fluorine is the best oxidant.

Reason: Fluorine is the most electronegative atom.

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: Higher the reduction potential value, the stronger the oxidising agent.

Among halogens, F2 is the best oxidant because it has the highest reduction potential value ($\mathrm{E}°$)