Use the Fundamental Identities to Simplify the Expression $\tan ( \mathrm { s } - \mathrm { t } )$

Multiple Choice

Use the fundamental identities to simplify the expression.
-Find $\tan ( \mathrm { s } - \mathrm { t } )$ given that $\cos \mathrm { s } = - \frac { 5 } { 13 }$ , with $\mathrm { s }$ in quadrant II, and $\sin \mathrm { t } = \frac { 8 } { 17 }$ , with $\mathrm { t }$ in quadrant II.

A) $- \frac { 220 } { 171 }$
B) $- \frac { 140 } { 171 }$
C) $\frac { 20 } { 3 }$
D) $- \frac { 20 } { 3 }$