Find the Values of the Variables for Which the Statement $\left[ \begin{array} { l } \mathrm { a } \\ 5 \\ 3 \end{array} \right] = \left[ \begin{array} { l } 3 \\ \mathrm { x } \\ 3 \end{array} \right]$

Find the values of the variables for which the statement is true, if possible.
- $\left[ \begin{array} { l } \mathrm { a } \\ 5 \\ 3 \end{array} \right] = \left[ \begin{array} { l } 3 \\ \mathrm { x } \\ 3 \end{array} \right]$

A) $\mathrm { a } = 5 ; \mathrm { x } = 3$
B) $\mathrm { a } = 3 ; \mathrm { x } = 3$
C) $a = 3 ; x = 5$
D) $a = 5 ; x = 5$