Find the sum upto $n$ terms of the G.P. $\sqrt 7,\sqrt {21},3\sqrt 7,.......$

Question

$\begin{array}{1 1}\sqrt 7.(\sqrt 3^n-1)(\sqrt 3+1) \\ \frac{\sqrt 7}{2}.(\sqrt 3^n-1)(\sqrt 3-1) \\\frac{\sqrt 7}{2}.(3^n-1) \\ \frac{\sqrt 7}{2}.(\sqrt 3^n-1)(\sqrt 3+1) \end{array}$