设随机变量<img src="https://static.zxtiku.com/wangke/imgs/topic/1c8f1dda93a2df753baf879865feee6c.jpg"/>的概率密度为<img src="https://static.zxtiku.com/wangke/imgs/topic/d8d102d36341be543a2e477010a81c4e.jpg"/>，且<img src="https://static.zxtiku.com/wangke/imgs/topic/29bad3119f4b3c7e0845235d60748bda.jpg"/>，则<img src="https://static.zxtiku.com/wangke/imgs/topic/a62a79c09976b51256b3cd2046c4c87a.jpg"/>（）. A. <img src="https://static.zxtiku.com/wangke/imgs/topic/b1b2b42a44c9c2370a0a8bb5d105a57d.jpg"/> B. <img src="https://static.zxtiku.com/wangke/imgs/topic/a5b5a0e4ed22c04c006a433d8d6ec6b4.jpg"/> C. <img src="https://static.zxtiku.com/wangke/imgs/topic/053a0772ff8a41e084a29b6265443063.jpg"/> D. <img src="https://static.zxtiku.com/wangke/imgs/topic/aadeba8bc150b7090f3732d4973b4668.jpg"/>