Which of the following sentences illustrates the proper use of apostrophes?

Which of the following sentences illustrates the proper use of apostrophes?

A. Helga borrowed her friend's skates for the day; however, she failed to return them.
B. Thousand's of bargains are available during the holiday season, but I cant find time to shop.
C. The koala bear closed it's eyes and fell fast asleep.
D. Although I like the Joneses, I'm angry at them for breaking all of Ralphs' tools.

Answer - A