Answer: The teacher packed picnic lunches for all the students—which they loved—and ate lunch outside with them at recess.
Which sentence contains a nonrestrictive clause and is punctuated correctly?

The punctuation of an adjective clause depends on whether it is essential (restrictive) or nonessential ( non-restrictive ) and uses commas accordingly. Essential clauses are not set off with commas; nonessential clauses are. An adjective clause is essential if the information it contains is necessary to the meaning of the sentence :

The choice of relative pronoun typically depends on whether the antecedent is human or a thing (that is a non-human): for example who and its derivatives (whom whoever etc.—apart from whose) are generally restricted to human antecedents while which and what and their derivatives refer in most cases to things including animals. The relative pronoun that is used with both human and non-human antecedents. Some writers and styl…

The punctuation of an adjective clause depends on whether it is essential (restrictive) or nonessential ( non-restrictive ) and uses commas accordingly. Essential clauses are not set off with commas; nonessential clauses are. An adjective clause is essential if the information it contains is necessary to the meaning of the sentence :

Dependent clause - Wikipedia

Clause - Wikipedia

Dependent clause - Wikipedia

Clause - Wikipedia

This is a non-restrictive clause ; it must be set off by commas and it must use the word which (or who for a person). Sentence A2 would have been correct English about 200 years ago but today it is simply wrong. That used in this way can only introduce a restrictive clause and a res...