I am considering the point you have given is point on a circumference of a circle and center of circle is (0,0) and we have to calculate radius
so radius = root((x-h)^2 + (y-k)^2)
where (h,k) is center of circle
so r = root((5-0)^2+(10-0)^2)
= √(100+25) = √125 = 5√5
so answer is option c