English Grammar and Vocabulary

Directions: Read the following lines and answer the question.

1. The child returned back home and was really too tired to exercise.
2. The first question asked from Raj in the interview was, ”what is your good name?”
3. The contest got an overwhelming response. They have yet to reply back.
4. He saw into the eyes of the thief and recognised him though he had covered his face.

Which word in line 3 can be omitted and still the sentence remains complete?