# If the vectors $\overline{AB} = 3 \hat{i} + 4 \hat{k}$ and $\overline{AC} = 5 \hat{i} - 2 \hat{j} + 4 \hat{k}$ are the sides of a triangles ABC, then the length of the median through A is
( A ) $\sqrt{33}$
( B ) $\sqrt{18}$
( C ) $\sqrt{45}$
( D ) $\sqrt{72}$