Under IAS 12, the disclosure requirements relate to information about income taxes. Of the options given, statement A. The aggregate current tax of CU 1,900 and deferred tax of CU 2,800 relate to items charged directly in equity is a disclosure that would typically be required under this standard, as it pertains to the allocation of taxes between equity and profit and loss in the financial statements.

Statement B. The current tax expense for the year ended 31 December 20X1 of CU 950 relates to turnover generated during the year could also be a valid disclosure, as it provides information about the relationship between the current tax expense and the operations of the entity.

However, statement C. During the year ended 31 December 20X1 there were no changes in the applicable income tax rate is not directly related to the disclosure requirements of IAS 12, which focuses on providing details about the calculation and recognition of income taxes, including current and deferred taxes, and how they are affected by temporary differences and transactions directly impacting equity.

Therefore, the most relevant disclosure according to IAS 12 would be a combination of options A and B, as they both pertain to the calculation and presentation of income taxes in the financial statements.