The author's attitude towards Nock's ideas is one of ______.

A．most men now choose to challenge normative marriage by making free choice
B．becoming a husband allows men achieve and sustain their masculinity
C．men show their determination in sustaining a key social institution through marriage
D．marriage expects different things of men from what it does of women

A．a survey of a book
B．a review of the recent trend in marriage
C．a scientific report
D．a preface to a book