Which sentence contains a non-defining (non-restrictive) clause?

Correct answer: My brother, who lives in Islamabad, is a doctor. “Who lives in Islamabad” is set off by commas and only adds extra information about “my brother”, so it is non-defining.

• The city where I was born is small: “Where I was born” is a defining clause that identifies which city is meant.
• The book that you lent me is great: “That you lent me” is a defining clause that identifies which book is meant.
• The woman who called you is outside: “Who called you” is a defining clause that identifies which woman is meant.