21. Let X be a strictly positive random variable, whose expectation equals to 0.5 and variance equals to 1. Which of the following statement is the most correct one? (A)Ein(2X)]＞0.5； (B)Elin(2X)]sO； (C)In(E[X])＞-0.2； (D)In(E[X2])＜-0.3； (E)2n(E[X])>-1.
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