Final answer:
Materiality influences the decisions of financial statement users (b) and is a key concept in financial audits because it helps auditors focus on significant matters, not immaterial details.
Step-by-step explanation:
Among the choices provided, the statement that best describes the role of materiality in a financial audit is b) Materiality influences the decisions of financial statement users.
Materiality is a foundational concept in auditing that determines the significance of an error or omission in financial statements. If a financial statement user's decision is likely to be changed or influenced by the error or omission, then it is considered material. Auditors use materiality as a threshold to assess which errors are significant enough to require correction before issuing their opinion on the financial statements. Conversely, immaterial errors are those that, either individually or in the aggregate, would not be expected to influence the decisions of users of the financial statements.
It is not solely determined by the auditor's discretion; auditors use guidelines and professional judgment to assess materiality. It's an important aspect of an audit because it helps auditors focus on matters that are significant to users of the financial statements, while not getting bogged down by inconsequential details.