In the following figure which of the following statements is true?

Answer: Option B

In Triangle ABD,
∠BAD + ∠B + 90° = 180°
or, ∠BAD + ∠B = 90° - - - - - - - (1)

Now, in Triangle ABC,
∠ACB + ∠B + ∠A = 180°
∠ACB + ∠B = 180° - 90°
∠ACB = 90° - ∠B - - - - - (2)
From (1) and (2), ∠BAD = ∠ACB
So, AC = CD