For positive x, y, how do the quadratic (RMS) and arithmetic means compare?

A √((x^2 + y^2)/2) ≥ (x + y)/2

B √((x^2 + y^2)/2) ≤ (x + y)/2

C √((x^2 + y^2)/2) = (x + y)/2 only when x ≠ y

D √((x^2 + y^2)/2) ≥ xy

Correct Answer: Option A