Find the Length of a Radius of the Circle $-$ 16 X

Multiple Choice

Find the length of a radius of the circle. 64 x 2 + 64 y 2 $-$ 16 x $-$ 112 y $-$ 2,446 = 0

A) $r = 1,521$
B) $r = 1$
C) $r = \sqrt { 39 }$
D) $r = 3 \sqrt { 39 }$
E) $r = 39$