In matrix equation [A]{X} = {R}
\[\left[ {\text{A}} \right] = \left[ {\begin{array}{*{20}{c}} 4&8&4 \\ 8&{16}&{ - 4} \\ 4&{ - 4}&{15} \end{array}} \right],\,\left\{ {\text{X}} \right\} = \left\{ {\begin{array}{*{20}{c}} 2 \\ 1 \\ 4 \end{array}} \right\}\,{\text{and }}\left\{ {\text{R}} \right\} = \left\{ {\begin{array}{*{20}{c}} {32} \\ {16} \\ {64} \end{array}} \right\}\]
One of the eigen values of Matrix [A] is

A. 4

B. 15

C. 8

D. 16

Answer: Option D