设随机变量X的E(X)=2,D(X)=3,用切比雪夫不等式估计P{|X—E(X)|≤3}≥ ()。
A <img src="https://www.beizhujiaoyu.com/uploads/202208/164696899974471.png" width="15" height="34" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/164696900340461.png" width="16" height="34" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/164696900891461.png" width="16" height="34" /> D 2