If x > 0, then 1/[√(2x)+√x] =

A. 1/√(3x)
B. 1/[2√(2x)]
C. 1/(x√2)
D. (√2-1)/√x
E. (1+√2)/√x

Correct answer = D

Could someone please show step by step how to get to this answer?

Thanks