If \(x\) is positive, which of the following could be correct ordering of \(\dfrac1{x}, 2x,\) and \(x^2?\)

I. \(x^2<2x<\dfrac1{x}\)

II. \(x^2<\dfrac1{x}<2x\)

III. \(2x<x^2<\dfrac1{x}\)

(A) none
(B) I only
(C) III only
(D) I and II
(E) I, II, and III

Answer: D

Source: GMAT Prep