Final answer:
The infinitive in the sentence 'Simone made the decision to read' is 'to read,' and it functions as a direct object, indicating what decision Simone made.
Step-by-step explanation:
In the sentence 'Simone made the decision to read,' the infinitive phrase is 'to read.' Here, the infinitive is the base form of the verb 'read' preceded by 'to.'
This infinitive functions nominally, acting as a direct object of the verb 'made.' It tells us what decision Simone made.
This is different from an adverbial use where the infinitive would modify the verb to tell us 'why' or 'how' something is done, or an adjectival use where it would modify a noun.
Note that in this sentence, the phrase 'made the decision' could be replaced by the action verb 'decided' for a more concise expression.