Answer: (C) is the right answer.The conclusion is AC = AD.
Explanation:
Let CD be any line and AB be the perpendicular bisector of CD bisects at O;i.e CO=OD...(1)
(with reference to the figure attached to the answer)
Construct two triangles ΔAOC and ΔAOD by joining A and C and A to D.
Then in ΔAOC and ΔAOD
CO=OD [from (1)]
∠AOD=∠AOD[90°]
AO=AO[common]
by SAS congruence criteria
ΔAOC ≅ ΔAOD
⇒AC=AD (corresponding parts of a congruent triangle are equal)
Hence the conclusion is AC = AD.