Option B (Liquidity) is correct because according to the textbook context, liquidity ratios are specifically calculated to measure the short-term solvency of the business, which is defined as 'the firm's ability to meet its current obligations.' The context clearly states that liquidity ratios measure 'the firm's ability to meet its current obligations' which directly corresponds to 'ability to satisfy its short-term obligations as they become due.' The other options are incorrect because: Activity ratios measure efficiency of operations and utilisation of resources; Debt (Solvency) ratios measure long-term obligations; and Profitability ratios analyse profits in relation to revenue or funds employed.