题目6单选题
<img src="https://tihai-oss-cloud.itihey.com/img/5724f08b7429306b85cde95012e88c2e.png">,则E(X)=( )A. <img src="https://tihai-oss-cloud.itihey.com/img/e059259dfc4ddd34cbaa4bc0c8bd8f3a.webp">B. <img src="https://tihai-oss-cloud.itihey.com/img/e98a8f4f69c864d2cb9ea7b5a9320bdd.webp">C. <img src="https://tihai-oss-cloud.itihey.com/img/f33bce2778d62bb4f0ed4f2596fce5a3.webp">D. <img src="https://tihai-oss-cloud.itihey.com/img/632395a1e79d8f99ac8b6015ae0f06b3.webp">