defer tax

(Source : IASplus) Deferred tax assets and liabilities are measured at the tax rates that are expected to apply to the period when the asset is realised or the liability is settled, based on tax rates/laws that have been enacted or substantively enacted by the end of the reporting period. [IAS 12.47] The measurement reflects the entity's expectations, at the end of the reporting period, as to the manner in which the carrying amount of its assets and liabilities will be recovered or settled. [IAS 12.51] KEY POINT IS WHETHER TAX LAWS ENACTED - SO (A) IN YOUR ANSWER ABOVE To be honest (b) means just about the same as (a). :)

And current tax is also measured based on tax rates that have been enacted or substantively enacted by end of reporting period?

Yes, that's right.