The quick ratio is a measure of a company's ability to pay off its short-term debts with its most liquid assets. It is calculated by subtracting the value of a company's stock (raw materials, work in progress, finished goods) from its current assets, and then dividing the result by the company's current liabilities.
So, the correct option is (3): x = current assets; y = stock and z = current liabilities. This is because the quick ratio formula subtracts the stock (inventory) value from the current assets to arrive at the most liquid assets available for paying off short-term obligations. And, the current liabilities reflect the company's immediate debts that must be paid off in the short term.