The correct option is D The store was for 'whites only'.
From the given options, D is correct as it's stated in the line "When Rosa and her cousin went to a local store for a soda, the girls were told that the store wouldn't serve them. They were asked to leave!". This is right after the lines that mention how fountains, restaurants and elevators were labeled 'whites only'. Options A, B and C are incorrect because none of them are mentioned in the passage. It's clearly mentioned "the girls were told that the store wouldn't serve them. They were asked to leave". It's also given that "Rosa Parks grew up in Alabama at a time when African-Americans were not treated the same as white Americans", and this was the only reason that Rosa and her cousin were asked to leave the store, because they would serve the 'whites only'.