My wife is learning English and she wrote the following sentence.
"When highlighting the large profit losses, the author identified a decrease in sales at Tasty Cream that is the only ice cream store in town."
She believes that this sentence is grammatically correct. However, I believe that using "Tasty Cream, which is the only ice cream store in town" or "Tasty Cream, the only ice cream store in town" is grammatically correct. Can someone help to explain which usage is correct and why? Thank you!