Which of the following best describes a rival good?

A rival good is defined as a type of good that is limited in availability and can only be consumed or used by one person at a time. This means that when one individual consumes or uses the good, it becomes unavailable for others, leading to competition over the resource. This concept is crucial in economics because it highlights how scarcity affects consumption and availability.

For example, if a specific fish in a lake is caught by one person, that fish cannot be caught by someone else, making the fish a rival good. This characteristic is important in discussions about resource management, environmental sustainability, and economic policies, as it influences how goods are allocated in society.

In contrast, other options describe different types of goods that do not reflect the essential defining feature of a rival good. Some goods are not rivalrous, allowing multiple users to consume them simultaneously (option A), while others may be public goods that are freely accessible to everyone (option C). Additionally, the requirement for payment (option D) relates to the nature of the good rather than its rivalness, as payment does not inherently limit use to one person at a time.