<p>A recent study shows that prescription drug use has gradually increased <u>among</u> people aged 50 years and above over the past decade.</p>The correct answer is "among".<div><br></div><div>The word "among" is used to indicate a group of people or things. In this sentence, it is used to show that prescription drug use has increased within the group of people aged 50 years and above. </div><div><br></div><div><span style="font-size: 13.008px;">(A)</span><span style="font-size: 13.008px;"> </span> "within" is not the correct choice because it is used to show something happening inside a particular group or area. It does not convey the idea of an increase among a group of people.</div><div><span style="font-size: 13.008px;">(C)</span> "around" is not the correct choice because it is used to show approximate numbers or quantities. It does not convey the idea of an increase among a group of people.</div><div><span style="font-size: 13.008px;">(D)</span> "between" is not the correct choice because it is used to show a relationship or comparison between two or more things. It does not convey the idea of an increase among a group of people.</div>