设<img src="https://static.zxtiku.com/wangke/imgs/topic/598eefa21835483f635c317ddc7d84d2.jpg"/>，则当<img src="https://static.zxtiku.com/wangke/imgs/topic/b46a2027fbaddb3e193c1414dba8e0fc.jpg"/>时，<img src="https://static.zxtiku.com/wangke/imgs/topic/6ec8a25184cfca96808e710b98bd618d.jpg"/>。<br/> A、-1<br/> B、1<br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/1d84b7938917dfb9dd4fff3144eba9c4.jpg"/><br/> D、0