Answer:
B √8
Step-by-step explanation:
Equation of a circle is:
(x − h)² + (y − k)² = r²
where (h, k) is the center and r is the radius.
The center of the circle is (1, 6).
(x − 1)² + (y − 6)² = r²
The circle passes through the point (-1, 8).
(-1 − 1)² + (8 − 6)² = r²
4 + 4 = r²
r = √8
