If \(A = \frac{1}{3}\left[ {\begin{array}{*{20}{c}} 1&2&a\\ 2&1&b\\ 2&{ - 2}&c \end{array}} \right]\)is orthogonal, then A-1 will be
1
\(\frac{1}{3}\left[ {\begin{array}{*{20}{c}} 1&2&2\\ 2&1&2\\ 2&{ - 2}&1 \end{array}} \right]\)
2
\(\frac{1}{3}\left[ {\begin{array}{*{20}{c}} 1&2&2\\ 2&1&{ - 2}\\ 2&2&1 \end{array}} \right]\)
3
\(\frac{1}{3}\left[ {\begin{array}{*{20}{c}} 1&2&2\\ 2&1&{ - 1}\\ 2&{ - 2}&1 \end{array}} \right]\)
4
\(\frac{1}{3}\left[ {\begin{array}{*{20}{c}} 1&2&2\\ 2&1&{ - 2}\\ 2&{ - 2}&1 \end{array}} \right]\)