Final answer:
The fundamental characteristic of useful accounting information is relevance. It helps users make informed decisions about the financial performance and position of an entity.
Step-by-step explanation:
The fundamental characteristic of useful accounting information is relevance. Relevant accounting information is able to influence the decisions and actions of its users. It is important because it helps users make informed decisions about the financial performance and position of an entity.
For example, relevant accounting information would include financial statements that provide information about a company's revenue, expenses, and assets. This information is relevant because it helps users assess the company's financial health and make decisions regarding investments, loans, or other financial transactions.
In contrast, the other options are also important in accounting, but they are not the fundamental characteristic of useful accounting information. Comparability is the ability to compare financial information across different time periods or between different entities. Neutrality refers to information that is free from bias. Materiality refers to information that is significant enough to influence the decision-making of users.