Women ______ drink more than two cups of coffee a day have a greater chance of having heart disease than those ______ don't.
　　A. who; 不填
　　B. 不填; who
　　C. who; who
　　D. 不填;不填
　　答案：C
　　解析：who引導(dǎo)定語(yǔ)從句，指代人，在從句中作主語(yǔ)，所以都不能省略。