Evaluate Without Using a Calculator $\tan \frac { \pi } { 4 }$

Multiple Choice

Evaluate without using a calculator. $\tan \frac { \pi } { 4 }$

A) $1$
B) $\text { undefined }$
C) $\frac { \sqrt { 3 } } { 2 }$
D) $\frac { \sqrt { 2 } } { 3 }$
E) 0