The correct options are "The sentence contains a restrictive clause", and "Only the lucky children got presents".
A restrictive clause is the use of an adjective to modify a certain word inside a sentence. This modification has to be crucial in determining the meaning of the entire phrase.
In this case, the word "lucky" acts as the modifier for "the children". It's a restrictive clause because it tells us that only the lucky children got presents. The word "lucky" is restricting the intended meaning of the phrase by excluding unlucky children.
Hope this helps!
