In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'.
He puts the birds softly, (1)/ one by one, interior their (2)/ warm little home./ (3) No Error (4)
Interior means situated on or relating to the inside of something, which does not fall right with the sentence. Instead of that, $in should be used.$