the complete question in the attached figure
we know that
the triangle AOB is congruent with triangle AOC
because
AB=AC
OB=OC-----> the radius of the circle
The OB side is common
but
there is no additional information that allows me to calculate the OBA angle to determine if it is a right angle
therefore
the answer is the option
C. There is no indication that AB and AC are perpendicular to the radii at the points of intersection with the circle.
