The number of purely real elements in a lower triangular representation of the given 3 × 3 matrix obtained through the given decomposition is _____\(\left[ {\begin{array}{*{20}{c}} 2&3&3\\ 3&2&1\\ 3&1&7 \end{array}} \right] = \left[ {\begin{array}{*{20}{c}} {{a_{11}}}&0&0\\ {{a_{12}}}&{{a_{22}}}&0\\ {{a_{13}}}&{{a_{23}}}&{{a_{33}}} \end{array}} \right]{\left[ {\begin{array}{*{20}{c}} {{a_{11}}}&0&0\\ {{a_{12}}}&{{a_{22}}}&0\\ {{a_{13}}}&{{a_{23}}}&{{a_{33}}} \end{array}} \right]^T}\)

• A. 7
• B. 6
• C. 8
• D. 9