Determine the Interval on Which the Vector-Valued Function $r ( t ) = 9 e ^ { - t } \mathbf { i } + e ^ { - t } \mathbf { j } + \ln ( t - 5 ) \mathbf { k }$

Multiple Choice

Determine the interval on which the vector-valued function $r ( t ) = 9 e ^ { - t } \mathbf { i } + e ^ { - t } \mathbf { j } + \ln ( t - 5 ) \mathbf { k }$ is continuous.

A) $( 9 , \infty )$
B) $( 5 , \infty )$
C) $[ 5 , \infty )$
D) $[ 9 , \infty )$
E) $( - 5 , \infty )$