Find the Fraction of a Circle That Encloses the Given $\frac { 1 } { 18 }$

Find the fraction of a circle that encloses the given angle.
-270°

A) $\frac { 1 } { 18 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 1 } { 17 }$
D) $\frac { 1 } { 9 }$