Answer:
Her porcelain doll, a rare collector’s item, was sold at auction.
✔ nonrestrictive
Chris went to Seattle to visit his aunt, a professional chef.
✔ nonrestrictive
The boy with the baseball cap would like to have a turn.
✔ restrictive
Step-by-step explanation:
A phrase is said to be restrictive (or otherwise called essential), if the word it modifies is narrowed down and it describes which noun it is writing about. They do not have commas and they are essential to the meaning of the sentence.
On the other hand, a nonrestrictive phrase describes a word whose meaning is already clear. As a result of this, it is not essential to the meaning of a sentence, therefore commas are used.