Answer:
AA
Step-by-step explanation:
∠ACD and ∠BCE are vertically opposite because they are opposite angles formed by two lines that cross. So, these angles have the same measure.
On the other hand, ∠DAC and ∠CEB are alternate interior angles. They are formed by two lines and a transversal and are in the interior of the lines and on opposite sides of the transversal. If the lines are parallel like this case, we get that these angles are equal.
So, ∠ACD = ∠BCE and ∠DAC = ∠CEB. It means that these triangles are similar by AA, because two of their interior angles have the same measure.