The correct answer is d. BAC ≅ ∠BDC.
How and why to ascertain this
The angles across from the legs of a right triangle are congruent. BD separates the hypotenuse into two segments, AD and DC, because it is an altitude to the hypotenuse. Angles ∠BAC and ∠BDC are both right angles since BD is perpendicular to AC. As a result, the angles ∠BAC and ∠BDC are equivalent (≅).
The other claims might not all be accurate. Triangles ADB and BDC, for instance, are not always congruent, and AB/BC is not always equivalent to AC/BD.