<p>Citizens are not <strong>eligible</strong> to receive the pension until they have reached the mandatory retirement age.</p>
<p>In this sentence, the correct answer is <strong>(A) eligible</strong>.</p>
<p>The word "eligible" is an adjective that means "having the right to do or receive something."</p>
<p>The other options are not correct:</p>
<p>(B) "Eligibleness" is not a word in English. The correct form of the word is "eligibility," which is a noun that means "the state of being eligible."</p>
<p>(C) "Eligibility" is a noun that means "the state of being eligible." Although this word is related to the correct answer, it does not fit grammatically in the sentence.</p>
<p>(D) "Eligibility" is a noun that means "the state of being eligible." Although this word is related to the correct answer, it does not fit grammatically in the sentence.</p>