If x and y are positive, which of the following must be greater that 1/sqrt(x + y)?
I. sqrt(x + y)/2x
II. [sqrt(x) + sqrt(y)]/(x + y)
III. [sqrt(x) - sqrt(y)]/(x + y)	Choose the correct choice from the following answers:
A) None  B) I only  C) II only  D) I and II  E) III and II
solving i ) Y &gt; X ( which could be true or false)   sloving ii) 2 Sqrt(xy) &gt; 0 ( which is true-given x and y are positive)   solving iii) -2 Squrt(xy) &gt; 0 ( which is false)   Therefore II only should be the answer.
<result>C</result>
If x and y are positive, which of the following must be greater that 1/sqrt(x + y)?
I. sqrt(x + y)/2x
II. [sqrt(x) + sqrt(y)]/(x + y)
III. [sqrt(x) - sqrt(y)]/(x + y)