Answer:
c)Triangle RDF is a right triangle.
Explanation:
Let us assume that we have a circle with center R, which has a radius(a line joining the center of a circle to a point on its circumference) RD. Drawing a tangent (a straight line that touches a circle at a point) externally to RD forms an angle of
with RD. Also, the tangent is perpendicular to RD if extended.
Therefore if we join R to F, we have a triangle RDF. The suitable option is that triangle RDF is a right triangle.