D. The impression the monk's stories had on me was profound.
Explanation:
An objective tone is characterized by the impartiality, factuality, and neutrality. Such tone is adopted by the author to propose a fair and equitable representation to the audience and avoid using personal pronouns like 'I', 'We', 'You', "Our' as they may reflect the author's personal opinions, emotions, or point of views. In the given question, option D evidently reflects the 'objective tone' as it employs third personal pronoun 'he' that serves to propose a neutral and unprejudiced(objective tone) description to the readers and let them decide their point of views instead inserting a pre-conceived perception(as occurs in first or second person point of views). The other options either employ personal pronoun like 'I'(in option B) or employ 'emotive words'(in options A and D) that proposes an opinion and hence, forbids them to offer an objective tone. Thus, option D is the correct answer.
