The sum of first $20$ terms of the sequence $0.7, 0.77, 0.777, ……,$ is :

Question

$\begin{array}{1 1} (1) \frac{7}{81} (179-10^{-20} ) \\ (2)\frac{7}{9} (99-10^{-20} ) \\ (3)\frac{7}{81} (179+10^{-20} ) \\(4) \frac{7}{9} (99 +10^{-20} ) \end {array}$