Final answer:
The adjective clause 'that is published by our school' in the sentence 'The newspaper that is published by our school is quite popular' is a restrictive clause.
Step-by-step explanation:
The adjective clause 'that is published by our school' in the sentence 'The newspaper that is published by our school is quite popular' is a restrictive clause.
Restrictive adjective clauses provide essential information about the noun they modify. In this sentence, the adjective clause is restricting the noun 'newspaper' to a specific one: the newspaper published by our school. Without this clause, the sentence would be incomplete and the meaning would be unclear.
So, the correct answer is B. restrictive.