Final answer:
The correct statement concerning the cash balance of a firm is that it can vary depending on its cash inflows and outflows.
Step-by-step explanation:
Out of the given statements, the correct one concerning the cash balance of a firm is 4) The cash balance of a firm can vary depending on its cash inflows and outflows.
The cash balance of a firm is not necessarily equal to its net income (statement 1), total assets (statement 2), or total liabilities (statement 3). Rather, the cash balance of a firm can change due to the cash coming into the firm (cash inflows) and the cash going out of the firm (cash outflows).