Determine All Solutions of the Equation in Radians $\cos ( \mathrm { s } - \mathrm { t } )$

Multiple Choice

Determine all solutions of the equation in radians.
-Find $\cos ( \mathrm { s } - \mathrm { t } )$ given that $\cos \mathrm { s } = - \frac { 4 } { 5 }$ , with $\mathrm { s }$ in quadrant II, and $\cos \mathrm { t } = \frac { 12 } { 13 }$ , with $\mathrm { t }$ in quadrant IV.

A) $- \frac { 63 } { 65 }$
B) $- \frac { 33 } { 65 }$
C) $\frac { 63 } { 65 }$
D) $-$