Answer
The answer is (c).
${\bf{r}}\left( t \right) = \left( {4,9,8} \right) + t\left( {0,1,0} \right)$.
Work Step by Step
The line equations in (a) - (d) all pass through the point $P = \left( {4,9,8} \right)$. However, only the line equation in (c) has direction vector ${\bf{v}} = \left( {0,1,0} \right) = {\bf{j}}$ that is perpendicular to the $xz$-plane.
So, the parametrization of the line through $P = \left( {4,9,8} \right)$ perpendicular to the $xz$-plane is ${\bf{r}}\left( t \right) = \left( {4,9,8} \right) + t\left( {0,1,0} \right)$.
