Why does the proportion of male conversation time devoted to "highbrow" subjects increase dramatically?

A. Because men think they are highbrow.
Because men like talking about highbrow subjects.
C. Because men want to impress women.
D. Because men are more likely to talk about highbrow subjects than women.

When women were present, men were more likely to discuss "(1)" and "(2)" subjects, such as(3)，(4)，(5)and(6) matters.

On their own, men gossip, with no more than(1)per cent of conversaition time devoted to non-social subjects; while in mixed groups, the proportion of male conversation time devoted to "highbrow" subjects increases to between(2) and(3) per cent.（请填数字）