Question

The center of a circle is at (−2, −7) and its radius is 6.

Answer 1

The correct option is C

Answer 2

It is C. There are multiple ways you can arrive to this. 
You might remember the formula for the circrle: 
(x-a)^2+(y-b)^2=r^2
where (a,b) is the center of the circle and r is the radius.