Insolvency occurs when a company's liabilities exceed its available assets, placing the company in a precarious financial state where it may not be able to meet its debt obligations. This state can lead to further legal and economic consequences, such as default or bankruptcy, but is itself the initial condition of financial distress. In the given scenario, if the liabilities of the company begin to outstrip its assets due to a significant revenue shortfall, the company would be considered insolvent.

A is incorrect. While the company's financial troubles may eventually lead to default, default specifically means the failure to meet financial obligations such as missed payments. Insolvency is the antecedent condition that creates a heightened risk of default.

B is incorrect. Operational risk is concerned with the risk resulting from inadequate or failed internal processes, people, and systems or from external events.