A、About 15%. B、About 25%. C、About 40%. D、About 50%. D题目问的是根据本文，有多少猫咬伤变感染了。由定位句可知，有50％的猫咬伤会被感染。故选D。

"A cat bite is nothing to trivialize," said Nancy Peterson, cat programs manager at the Humane Society of the United States. Up to 50 percent of cat bites become infected, said Princy N. Kumar, head of the infectious-diseases division at MedStar Georgetown University Hospital. But many people underestimate the danger, Kumar said, and don’t realize they should get a bit looked at right a-way. "If you got a really bad bite, you should get prophylactic antibiotics," Kumar said. A light nip is not a problem, she said, but seek help if the cat has really sunk its teeth in—" if you see a puncture wound and blood coming out of it. "
    Q16: According to the passage, how many of the cat bites become infected?
    Q17: What does Kumar say about cat bites?
    Q18: When don’ t people have to seek medical help if they are bitten by a cat?