题目解析:
题干提问“作者为什么讨论爸爸和其他男性的声音”。
定位第7段第3句 As support for this conjecture, researchers point to the fact that newborns do not show a preference for their fathers’ voices over other male voices.
根据 as support for this conjecture 得知 their fathers’ voices over other male voices 是作为论据支持 this conjecture;this conjecture 指代前一句 prenatal exposure to the mother’s voice is the key.
再结合段尾句 the prenatal exposure to their mothers’ voices—although muffled by the liquid environment of the womb—helps shape infants’ listening preferences.
综合以上内容,均可得出其论点为婴儿的听力偏好会在产前就会受到影响。
故选 B。