本题考查对“语义缩小”的理解。
SEMANTIC BROADENING（语义扩大）

The older meaning of "aunt" was father's sister, but its modern referent can also be mother's sister.

以前“aunt”的意思是父亲的姐姐，但是现在的指示对象也包括母亲的姐姐。

SEMANTIC NARROWING（语义缩小）

（1）The Old English version of the word "wife" could be used for any woman, but has narrowed in its modern application to only married females.

古英语版本中的“wife”一词可以指代任何一个女人，但是词义发生了缩小，现在仅应用于指代结婚的女性。

（2）An example of semantic narrowing that occurred is Old English "hund"("hound"), a word which was once used for any breed of dog; whereas in Modern English the meaning has been narrowed to a particular kind of dog.

一个典型的词义缩小的例子是古英语中的“hund”（“hound”）这个词，以前指代任何品种的狗，现在是特定一种品种的狗。

（3）The older usage of the word "fowl" included both wild and domesticated birds, but today is restricted to the latter only.

“fowl”一词的古老用法包括野生和驯养的鸟类，但今天仅限于后者。

A选项aunt为语义扩大的例子，BCD三项为语义缩小的例子，故选A。