Adult female rats who have never before encountered rat pups will start to show maternal behaviors after being confined with a pup for about seven days. This period can be considerably shortened by disabling the female’s sense of smell or by removing the scent-producing glands of the pup.

Which of the following hypotheses best explains the contrast described above?

(A) The sense of smell in adult female rats is more acute than that in rat pups.

(B) The amount of scent produced by rat pups increases when they are in the presence of a female rat that did not bear them.

(C) Female rats that have given birth are more affected by olfactory cues than are female rats that have never given birth.

(D) A female rat that has given birth shows maternal behavior toward rat pups that she did not bear more quickly than does a female rat that has never given birth.（E）

(E) The development of a female rat’s maternal interest in a rat pup that she did not bear is inhibited by the odor of the pup.

能不能给翻译和解释一下文章和正确选项？

没有接触过小鼠（隐含意思：未生育过小鼠）的成年母鼠 当把他们和幼鼠关在一起7

天后 开始显露出母性

但是如果通过降低母鼠的嗅觉能力或者移除小鼠的制造气味的腺体 显露母性的时间将会

缩短

e选项：母性的形成会被小鼠身上产生的气味所抑制

但是不明白题目中contrast只的是什么