A Paired Difference Experiment Yielded $\mathrm { n } _ { \mathrm { d } }$

Multiple Choice

A paired difference experiment yielded $\mathrm { n } _ { \mathrm { d } }$ pairs of observations. For the given case, what is the rejection region for testing $\mathrm { H } _ { 0 } : \mu _ { \mathrm { d } } = 9$ against Ha: $\mu _ { \mathrm { d } } \neq 9$ ?
$$\mathrm { n } _ { \mathrm { d } } = 13 , \alpha = 0.05$$

A) $t > 1.782$
B) $t > 2.179$
C) $| t | > 2.160$
D) $| t | > 2.179$