Answer: <CDB corresponds to <ECD
Step-by-step explanation:
The angles in similar triangles correspond to each other.
For two angles in similar triangles to correspond to each other, then they have to be in the same position in the triangle. (EX: a 90 degree angle corresponds to another 90 degree angle or an angle across from the shortest side corresponds to another angle in the other triangle across from the shortest side)
In this case, <CDB is to the right of the 90 degree angle, so the angle it will correspond to is the angle in the other triangle which is opposite to the 90 degree angle, which is <CED.
<CED is not <ECD, so that answer is wrong.
Tell me if I need to clarify anything - this topic is kind of hard to explain :/