In each question below, a sentence is given with an idiom/phrase printed in bold type. That part may contain a grammatical error. Each sentence is followed by four alternatives. Find out which option should replace the phrase/idiom given in bold to correct the error, if there is any, and to make the sentence grammatically meaningful and correct. If the sentence is correct as it is and ‘No correction is required’, mark 5) as the answer. He and his neighbour are always on logger heads.