The value of $a^2+ab+b^2$ if $a=\large\frac{\sqrt 2+1}{\sqrt 2-1}$ and $b=\large\frac{\sqrt 2-1}{\sqrt 2+1}$ is ______

Question

$\begin{array}{1 1}(A) \;36\\(B)\;35 \\(C)\;30 \\(D)\;1 \end{array}$