Research Suggests That the Benefits of a Parent's Taking Family

Research suggests that the benefits of a parent's taking family leave after the birth of a baby

A) are greater if the leave is longer (e.g, 4 months) rather than shorter (2 months or less)
B) are greater if the baby has a difficult rather than an easy temperament
C) have yet to be established
D) are greater if the leave is longer rather than shorter and are greater if the baby has a difficult rather than an easy temperament
E) none of these