Question

Which triangles are congruent by ASA?

Answer 1

Side BC is congruent to side DC. (That's what the hash marks mean.) Angle C is congruent with itself, and the right angles at B and D are all congruent.

Thus, you want to choose triangle names that show BC congruent to DC. The appropriate selection is the second one ...
  ∆ADC ≅ ∆EBC

Answer 2

Angle C is congruent to angle C. (A pair of angles)
Side CB is congruent to side CD. (A pair of sides)
Angle CBE is congruent to angle CDE. (A pair of angles)

By ASA, triangles CBE and CDA are congruent.

That is another way of naming triangles ADC and EBC.

Answer: Second choice.