The statements that accurately describe the sentence are:
• The sentence contains a nonrestrictive clause: a nonrestrictive clause provides additional information to the sentence but it does no alter the meaning of the sentence if it is removed from it. In this case the nonrestrictive clause is “who were lucky”. Nonrestrictive clauses should be delimited by commas within the sentence.
• All of the children got presents: the meaning of the sentence exemplifies that all children got presents since the nonrestrictive clause adds optional meaning and if it were removed, the sentence would say “The children got presents”.
