Find a Unit Vector Perpendicular to the Plane Determined by the Points

Multiple Choice

Find a unit vector perpendicular to the plane determined by the points $P ( 1,2,3 ) , Q ( 4,5,6 ) \text {, and } R ( 1,1 , - 1 )$

A) $\left\langle \frac { 3 } { \sqrt { 26 } } , - \frac { 4 } { \sqrt { 26 } } , \frac { 1 } { \sqrt { 26 } } \right\rangle$
B) $< \frac { 3 } { \sqrt { 26 } } , \frac { 4 } { \sqrt { 26 } } , \frac { 1 } { \sqrt { 26 } } >$
C) $< \frac { 3 } { 26 } , - \frac { 4 } { 26 } , \frac { 1 } { 26 } >$
D) $\left. < \frac { 3 } { 26 } , \frac { 4 } { 26 } , \frac { 1 } { 26 } \right\rangle$