In Each Set Below, Select the Letter of the Sentence

Multiple Choice

In each set below, select the letter of the sentence in which all of the apostrophes are used correctly. In which sentence are apostrophes used correctly?

A) During the summer of '09, my friend's spent a week at my aunt's house in Alaska.
B) During the summer of '09, my friends' spent a week at my aunts house in Alaska.
C) During the summer of '09, my friends spent a week at my aunt's house in Alaska.