请教一道逻辑题

Psychological maladjustment in children is caused by the stress of the birthing process as is proved by the discovery of a positive relationship between the duration of the mother's labor and the amount of time the child spent crying in the first month of life.

Which of the following, if true, LEAST damages the author's assertion?

(A) There is no relationship between the amount of time spent crying and psychological maladjustment.
(D) The estimates of the duration of labor were based on obstetricians' estimates of the time of the onset of labor.
(E) The infants who have experienced the greatest stress during birth are often too weak to cry for extended periods of time.

有两个问题求教，
1）看到这样的题目‘LEAST damage'是不是意味着答案中有4个都是'damage'原文结论的，只是有一个选项与原文结论大致无关？
2）这三个答案哪个正确？我觉得D在支持原文assertion，而A、E与原文assertion无关。