Restrictive vs Non-restrictive Relative Clause

Solution 1:

The non-restricting version gives extra information about the location (it was called Central Park). The restricting version helps you find your memory of the location (the location that was called Central Park). The preferred methods are to use 'that' to restrict, and to use ', which' to give extra (adverbial) info.

Solution 2:

The reference of C (the places it could refer to) is a subset of the references of A or B. But the references of A and B are equal. In this sense, the relative clause of C is "restrictive", since it restricts the reference of A.

• A. the location (with no relative clause)
• B. the location, which was called Central Park,
• C. the location which was called Central Park