What will be an ideal response?
The time inconsistency of optimal policy refers to game theory situations where an agent has an incentive to deviate from some stated rule/policy. In terms of monetary policy, central banks will typically announce certain goals (e.g. policies consistent with a certain rate of inflation). Once such a policy is announced, the central bank might have an incentive to deviate from this policy and increase money growth in excess of the rate consistent with its inflation goal. There would be some increase in inflation; however, there would be a significant increase in output.