Choose the sentence that is written correctly.
my favorite stores are bloomingdale's and macy's. my sister only shops at nordstrom.
my favorite stores are bloomingdale and macy. my sister only shops at nordstroms.
my favorite stores are bloomingdales and macys. my sister only shops at nordstroms.
my favorite stores are bloomingdales and macy's. my sister only shops at nordstrom.

The correct answer is A. My favorite stores are Bloomingdale's and Macy's. My sister only shops at Nordstrom.
The names of the shops are Bloomingdale's, and Macy's - both of these shops have the apostrophe and then -s in their actual name, so these cannot be omitted. The third shop doesn't have an apostrophe and -s: its name is just Nordstrom. This is why the other options are incorrect.