What Angle Corresponds to a Circular Arc on the Unit $\frac{180^{\circ}}{7 \pi}$

What angle corresponds to a circular arc on the unit circle with length 7? Give the exact answer in degrees.

A) $\frac{180^{\circ}}{7 \pi}$
B) $\frac{630^{\circ}}{\pi}$
C) $\frac{90^{\circ}}{7 \pi}$
D) $\frac{1,260^{\circ}}{\pi}$