$14.-$ The rigid pole and cross$-$arm assembly is supported by the three cables shown. A turnbuckle at $D$ is tightened until it induces a tension $T$ in $CD$ of $2\mathrm{.}1$ kN $.$ Determine the vector expression for the moment of the $2\mathrm{.}1-kN$ tension about point $B.$

Comprehension $($State Definition, Free Body Diagram and$/$or Diagram Sketch$)$