Use the Fundamental Identities to Find the Value of the Trigonometric

Use the fundamental identities to find the value of the trigonometric function.
-Find $\cos \theta$ if $\tan \theta = \frac { 2 } { 5 }$ and $\theta$ is in quadrant III.

A) $\frac { \sqrt { 33 } } { 4 }$
B) $- \frac { 5 \sqrt { 29 } } { 29 }$
C) $\frac { 4 } { 5 }$
D) $- \frac { \sqrt { 11 } } { 6 }$