For ASA to be used, 2 angles and their included side must be congruent. ∠F ≅ ∠E because of the markings, ∠E ≅ ∠F because all right angles are congruent, and side FE ≅ EF because they are aligned with each other. 2 angles and their included side are congruent.
As for the congruence statement, D is the right answer because ∠D ≅ ∠G, ∠E ≅ F, and ∠F ≅ ∠E.