根据以下内容回答题：A youngster"s social development has a profound effect on his acad

根据以下内容回答题：

A youngster"s social development has a profound effect on his academic progress．Kids who have trouble getting along with their classmates can end up behind academically as well and have a higher chance of dropping out（退学）．In the early grades especially，experts say，youngsters should be encouraged to work in groups rather than individually so that teachers can spot children who may be having problems making friends．“When children work on a pro-ject，”says Lillian Kate，an educational professor at the University of Illinois，“they learn to work together，to disagree，to think to take turns and lighten tensions．These skims can’t be learned through lecture．We all know people who have wonderful technical skills but don’t have any social skills．Relationships should be the first R．”At a certain age，children are also learning to judge themselves in relation to others．For most children，school marks the first time that their goals are not set by an internal clock but by the outside world．Just as the l-year-old struggling to walk the 6-year-old is struggling to meet adult expectations．“Young kids don’t know how to distinguish early-childhood education for the state of New Jersey，if they try hard to do something and fail，they may conclude that they will never be able to accomplish a particular task．The effects is serious，”says Hills，“a child who has had his confidence really damaged needs a rescue operation．”

The author seems to think that a kid’S poor relationship with his classmates would__________ ．

A.have negative effects on his study

B.develop his individualism but limit his intelligence

C.eventually lead to his leaving school

D.have nothing to do with his achievements in a course