<p>The National Tax Administration will deposit your tax refund directly into the <strong>designated</strong> bank account on the tax refund date.</p><div data-answer="a"><span>The correct answer is </span><strong style="font-size: 13.008px;">(A) designated</strong><span>.</span></div><p>In this sentence, the word "directly" indicates that the tax refund will be deposited into a specific bank account. Therefore, the bank account must be <strong>designated</strong> or chosen beforehand for this purpose.</p><p>The word "mandatory" (option B) means required or obligatory, but it does not convey the idea of choosing or specifying a bank account. Therefore, it is not the correct answer.</p><p>The word "approximate" (option C) means close to the actual amount or time, but it does not relate to the bank account being used for the tax refund deposit. Therefore, it is not the correct answer.</p><p>The word "invalid" (option D) means not legally or officially acceptable, which is not relevant to the context of the sentence. Therefore, it is not the correct answer.</p>