题目3单选题
函数<img src="https://tihai-oss-cloud.itihey.com/img/43727cb966ad1c03aae96cc3c417c84e.png">在<img src="https://tihai-oss-cloud.itihey.com/img/ff3565c89ac0ac9f28619dddae9b0862.png">处取得极大值,则必有( )A. <img src="https://tihai-oss-cloud.itihey.com/img/74a3039bec77be9e6807e93177d2d118.png">B. <img src="https://tihai-oss-cloud.itihey.com/img/74a1041a746388cb32d689747eda83c9.png">C. <img src="https://tihai-oss-cloud.itihey.com/img/74a3039bec77be9e6807e93177d2d118.png">且<img src="https://tihai-oss-cloud.itihey.com/img/74a1041a746388cb32d689747eda83c9.png">D. <img src="https://tihai-oss-cloud.itihey.com/img/74a3039bec77be9e6807e93177d2d118.png">或<img src="https://tihai-oss-cloud.itihey.com/img/33eece296bf07e3820b73e66cb1783ba.png">不存在