Find the Exact Value of the Expression Using the Provided $\tan ( \mathrm { s } - \mathrm { t } )$

Find the exact value of the expression using the provided information.
-Find $\tan ( \mathrm { s } - \mathrm { t } )$ given that $\sin \mathrm { s } = - \frac { 3 \sqrt { 13 } } { 13 }$ , with $\mathrm { s }$ in quadrant $\mathrm { IV }$ , and $\sin \mathrm { t } = - \frac { \sqrt { 10 } } { 10 }$ , with $\mathrm { t }$ in quadrant IV.

A) $- \frac { 11 } { 9 }$
B) $\frac { 11 } { 3 }$
C) $- \frac { 11 } { 3 }$
D) $- \frac { 7 } { 9 }$