\(\triangle ABC,\) which is right-angled at \(B,\) is inscribed in a circle with center \(O\) and radius \(6\) units. If the length of the smaller arc between points \(A\) and \(B\) is \(4\pi\) units, what is the length of line segment \(BC?\)
A. \(3\)
B. \(\pi\)
C. \(3\sqrt3\)
D. \(6\)
E. \(2\pi\)
Answer: D
Source: e-GMAT