C. Tax rates that had been enacted at the time should be updated for subsequent changes in tax rates.

The statement is false according to the principles of first-time adoption of IAS 12, International Accounting Standard on Income Taxes. When adopting IAS 12 for the first time, an entity is generally not required to update the tax rates for subsequent changes in tax rates that occurred after the initial enactment. Instead, the tax rates that were in effect at the beginning of the earliest comparative period presented should be used to determine the related deferred tax liabilities and assets. Therefore, the entity would not update the tax rates for subsequent changes, but should apply the tax rates that were in effect at the time when the transactions or events giving rise to temporary differences occurred.