Concept:A simile is a figure of speech that compares two different things using the word “like” or “as”.Explanation:The phrase “like a fly that dared not alight” uses the word “like” to compare Grooby’s restless mind to a fly.This comparison shows that his thoughts are agitated and unable to settle, just as a fly avoids landing.Since the comparison is made directly with “like”, it is a classic example of a simile.It is not hyperbole, irony, or alliteration, because none of those devices match this construction.Answer:A. simile