You can re-arrange your sentence in this way:
In order to identify the development of tornadoes, few required conditions can be described.
Revision involves clarifying purpose and meaning.
All other choices would be incorrect because they are a part of the process of editing.
Answer: A. The hopeful actors agreed to meet in the dressing room before the audition.
Explanation: An adverb phrase is simply a phrase that acts as an adverb to describe a verb, adverb, or adjective. Adverb phrases typically answer the questions how, where, why or when something was done. From the given options, the sentence that contains an adverbial phrase is the corresponding to option A: The hopeful actors agreed to meet in the dressing room before the audition, the adverbial phrase "before the audition" answer the question "when."
