化简 $\sqrt{1+\frac{1}{n^2}+\frac{1}{{\left(n+1\right)}^2}}\mathrm{（}n>0$或 $n<-1$）所得的结果为（ ）

A．	$1+\frac{1}{n}+\frac{1}{n+1}$	B．	$1-\frac{1}{n}+\frac{1}{n+1}$
C．	$1+\frac{1}{n}-\frac{1}{n+1}$	D．	$1-\frac{1}{n}-\frac{1}{n+1}$