Option C
The radius of circle is 13 units
<em><u>Solution:</u></em>
<em><u>The equation of circle is given by formula:</u></em>
Where, the center being at the point (h, k) and the radius being "r"
<em><u>Given that circle has its center at the origin</u></em>
(h, k) = (0, 0)
<em><u>(5, -12) is a point on the circle</u></em>
(x, y) = (5, 12)
<em><u>Substituting in equation we get,</u></em>
Thus radius of circle is 13 units