Being a parent is not always easy ,and being.代词的用法,请教

Being a parent is not always easy ,and being.代词的用法,请教
Being a parent is not always easy ,and being the parent of a child with special needs often carries with ______extra stress . A.it B.them C.one D.him 为什么选A?答案说的是指代the parent of a child with special needs ,可是,怎么看都觉得不对.后面加的extra stress觉得不通顺还是位置很奇怪什么的~~~~