Answer:
A: The chord is perpendicular to the diameter
Proof:
CE=DE (definition of bisector)
Center O, so OC and OD are radii.
OC=OD.
OE=OE.
OCE=ODE (SSS)
angle OEC = angle OED (corresponding parts)
angle OEC and angle OED are supplementary
So angle OEC and angle OED are both right angles.
CD is perpendicular to OE
CD is perpendicular to AB
