Final answer:
Supplemental balance sheet information that addresses material events with uncertain outcomes is referred to as contingencies.
Step-by-step explanation:
The correct answer is A. Contingencies.
Supplemental balance sheet information that addresses material events with uncertain outcomes is known as contingencies. Contingencies are potential obligations or liabilities that depend on the occurrence or non-occurrence of future events and may require disclosure in financial statements.
For example, a company may be involved in a lawsuit where the outcome is uncertain. In this case, the company would disclose the lawsuit as a contingency in its supplemental balance sheet information to inform investors and stakeholders about the potential impact on the company's financial position.