Use a Sum or Difference Identity to Find the Exact $\tan 105 ^ { \circ }$

Multiple Choice

Use a sum or difference identity to find the exact value.
- $\tan 105 ^ { \circ }$

A) $2 + \sqrt { 3 }$
B) $\frac { 2 - \sqrt { 3 } } { 4 }$
C) $- 2 - \sqrt { 3 }$
D) $\frac { 2 + \sqrt { 3 } } { 4 }$