The answer is A) before you go to bed, make sure the oven is turned off.
The sentence that contains an adverb clause is 'Before you go to bed, make sure the oven is turned off.' An adverb clause like 'Before you go to bed' provides additional context to the actions within a sentence. ;
The sentence that contains an adverb clause is A: 'Before you go to bed, make sure the oven is turned off.' The adverb clause 'Before you go to bed' provides context by indicating when to perform the action of making sure the oven is turned off. All other options do not contain adverb clauses and simply state facts.
;