Which sentence does not use an adverb clause as a modifier?
a) the dog under the bed whined while the garbage trucks drove by.
b) without a clear goal , it is very difficult to make an effective plan.
c) no one was sure where helen was until she finally called the office back.
d) fitz lost his parking privileges when he came to school late five days in a row.

The answer to your question would be that the sentence that does not use an adverb clause as a modifier is the following one: Without a clear goal, it is very difficult to make an effective plan. That is, the correct option would be B.

An adverb clause is a group of words that functions as an adverb in a sentence. As a clause, adverb clauses have a subject and a verb. On the contrary, phrases do not have a subject and a verb. Sentence B does not contain an adverb clause but a prepositional phrase as a modifier ("without a clear goal").

if this is a true or false question its true