In Gottman and His Colleagues's "Love Lab" Studies, Married Couples

In Gottman and his colleagues's "love lab" studies, married couples are observed in an apartment where their verbal, nonverbal and physiological responses are carefully recorded. Gottman found that happy/stable couples were distinguished from those headed for divorce by

A) the presence or absence negative behaviors.
B) the presence or absence of love and affection.
C) the ratio of positive to negative behaviors.
D) the degree of mutual support and affirmation.