阅读下列短文,从每小题所给的A、B、C、D四个选项中选出一个最佳选项。

    Tu Youyou, aged 85, is a medical scientist at the China Academy of Traditional Chinese Medicine. she has just become the first Chinese woman to win a Nobel prize, for helping discover artemisinin, a new kind of medicine known as "Qing-hao-su" in Chinese in 1971 and dihydroartemisinin, used also to treat malaria(疟疾).

    The discovery of “Qing-hao-su” and its use in treating malaria are regarded as the most important breakthrough(突破) in tropical medicine in the 20th century. It is also a major health improvement for people in developing tropical countries in south Asia, Africa, and South America.

    This is the first time her work has been widely recognized in China, and it also marks the first time China has won a Nobel prize in the sciences.The last time a Chinese national won a Nobel Prize was in 2012, when Mo Yan got the literature award.

    Tu also received several medical awards in the past including the 2011 Lasker Award in Clinical Medicine for the same achievements.Tu was the first native Chinese who was educated and works in China to win the Lasker award, too.

（2017•新课标Ⅱ）设O为坐标原点，动点M在椭圆C： $\frac{x^2}{2}$ +y²=1上，过M做x轴的垂线，垂足为N，点P满足 $\overrightarrow{NP}$ = $\sqrt{2}\overrightarrow{NM}$ ．

（Ⅰ）求点P的轨迹方程；

（Ⅱ）设点Q在直线x=﹣3上，且 $\overrightarrow{OP}$ • $\overrightarrow{PQ}$ =1．证明：过点P且垂直于OQ的直线l过C的左焦点F．

    自三峡七百里中，两岸连山，略无阙处。重岩叠嶂，隐天蔽日，自非亭午夜分，不见曦月。

    至于夏水襄陵，沿溯阻绝。或王命急宣，有时朝发白帝，暮到江陵，其间千二百里，虽乘奔御

    风，不以疾也。

    春冬之时，则素湍绿潭，回清倒影，绝巘多生怪柏，悬泉瀑布，飞漱其间，清荣峻茂，良多趣味。

    每至晴初霜旦，林寒涧肃，常有高猿长啸，属引凄异，空谷传响，哀转久绝。故渔者歌曰：“巴东三峡巫峡长，猿鸣三声泪沾裳。”

若分式$\frac{x^2-9}{x+3}$的值为零，则x的取值为（     ）