Which of the following is the inverse of the matrix \(A = \left[ {\begin{array}{*{20}{c}} 3&0\\ 1&2 \end{array}} \right]\)
1
\(\left[ {\begin{array}{*{20}{c}} {\frac{1}{3}}&0\\ { - \frac{1}{6}}&{\frac{1}{2}} \end{array}} \right]\)
2
\(\left[ {\begin{array}{*{20}{c}} 0&{\frac{1}{6}}\\ { - \frac{1}{6}}&{\frac{1}{2}} \end{array}} \right]\)
3
\(\left[ {\begin{array}{*{20}{c}} {\frac{1}{3}}&{ - \frac{1}{6}}\\ {\frac{1}{3}}&{\frac{1}{2}} \end{array}} \right]\)
4
\(\left[ {\begin{array}{*{20}{c}} {\frac{1}{3}}&0\\ 0&{\frac{1}{2}} \end{array}} \right]\)