阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。

A

A giant panda at Washington’s zoo surprised scientists and zookeepers by becoming a mom again after years of failed pregnancies.

Scientists at the zoo had all but given up on 14-year-old Mei Xiang’s chances of pregnancy. However, she gave birth again on late Sunday, ten years after her first cub, a male named Tai Shan, was born in 2005. Officials will follow Chinese custom and give it a name after 1 00 days. Mei Xiang and her mate Tian Tian, born in China, are the second pair of pandas to live at the zoo. They’re treated very kindly.

Since 2007, zoo officials have had five unsuccessful attempts at artificially inseminating(人工受精) Mei Xiang. But each time there was no cub. As a result, they had considered replacing Mei Xiang or 15-year-old Tian Tian with other pandas. Still, there was hope.

For now, keepers said，Mei Xiang is doing well and responding to the noisy cub. Under an agreement with the Chinese government, zoo officials can keep the cub for four years before it has to go back to China, just as its older brother Tai Shan did in 2010.

Still, there’s some danger for the cub, especially in the next two weeks. Pandas have accidentally crushed(挤压) their small cubs. And the zoo’s first panda couple, Ling-Ling and Hsing-Hsing, had five cubs, but none of them survived more than a few days.