We Need To Go Radically Deeper

Algebra Level 3

$\large \sqrt{ x \sqrt[3]{x \sqrt[4]{x \sqrt[5]{ x \cdots }} }}$

Let $e = 2 + \dfrac1{1\times2} + \dfrac1{1\times2\times3}+ \dfrac1{1\times2\times3\times4} + \cdots$.

Which of the following is equal to the expression above. (Take $x\geqslant 0$)

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