What defines a liability account?

A liability account is defined by its purpose of tracking the obligations that a company owes to outside parties. This includes debts such as loans, accounts payable, mortgages, and any other commitments that the company must fulfill in the future. These obligations create a future outflow of resources, which is a critical aspect of what constitutes a liability.

In contrast, the other options describe different types of accounts in financial accounting. For instance, accounts that track investments in the company relate to equity, which reflects the owner's stake in the business. An account reflecting owner's equity provides insights into the ownership structure and value of the business from the perspective of the owners. Similarly, an account that measures revenues generated focuses on income earned from business activities, which is part of the overall performance assessment of the company. Each of these options serves distinct purposes in the financial accounting framework, differentiating them clearly from the role of liability accounts.