1952年，哈理马柯威茨发表了一篇题为《证券组合选择》的论文。这篇著名的论文标志着现代证券组合理论的开端。 ( )

One afternoon, my son Adam asked me, "Are all people the same even if they are different in color " I thought for a minute, and then I said, "I’ll explain,（1）you can just wait until we make a quick stop at the grocery store. I have something （2） to show you. "At grocery store, we bought some apples-red, green and yellow ones. Back home, I told Adam, "It’s time to（3） your question." I put one apple of each type on the table. Then I looked at Adam, who had a （4） look on his face."People are like apples. They come in all different colors, shapes and sizes. On the（5）, some of the apples may not even look as the others. " As I was talking, Adam was（6）each one carefully. Then, I took each of the apples and peeled them, placing them back on the table, but （7） a different place."Okay, Adam, tell me which is which." He said, "I can’t tell. They all look same now." "Take a bite of （8）. See if that helps you decide which one is which. "He took（9） , and then a huge smile came cross his face. "People are just like apples! They are all different, but once you（10）the outside, they’re pretty much the same on the inside. "He totally got it. I didn’t need to say or do anything else.

第（3）空应选择（）

A. check

B. mention

C. answer 

D. improve