Find the Angle Between the Vectors $\mathbf { u }$ And $\mathbf { v }$

Multiple Choice

Find the angle between the vectors $\mathbf { u }$ and $\mathbf { v }$ . Express your answer in degrees and round to the nearest tenth of a degree.
$$\mathbf { u } = 6 \mathbf { i } - 3 \mathbf { j } - 9 \mathbf { k } , \mathbf { v } = - \mathbf { i } - \mathbf { j } - 6 \mathbf { k }$$

A) $36.4 ^ { \circ }$
B) $47.5 ^ { \circ }$
C) $53.6 ^ { \circ }$
D) $90 ^ { \circ }$
E) $42.5 ^ { \circ }$