State the Period of the Function $$y = \frac { 1 } { 2 } \sec \frac { \pi x } { 4 }$$

Multiple Choice

State the period of the function. $$y = \frac { 1 } { 2 } \sec \frac { \pi x } { 4 }$$

A) 12
B) $\frac { \pi } { 4 }$
C) 10
D) 8
E) $8 \pi$