Answer:
AC=BD
CAD=CBD
ACB=ADB
Explanation:
You're essentially looking for anything of equal proportions. Obviously, your circle is split by several lines, and each side is symmetric. Since you know this, it's simply a matter of identifying one element then finding its symmetric match.
Follow the lines and trace the path with your finger for each question. If you do this, you'll see that AC=BD is an answer that involves a symmetric pair, because these two are equal distances and equal (but opposite) in placement.
Continuing with this method, keep track of the parts of the triangles you trace. With CAD=CBD, you trace across a hypotenuse, a leg, and a base in BOTH, making this true.
Continuing further with ACB=ADB, you trace across a hypotenuse, a leg, and a base with both AGAIN, making this true.
With AB=CD, this is obviously incorrect. You can't jump between points.