Concept:The quick ratio, also called the acid-test ratio, measures how well a business can meet its short-term debts using its most liquid current assets.It excludes stock or inventory because stock may not be quickly converted into cash.Explanation:The standard formula for the quick ratio is:Quick Ratio=Current LiabilitiesCurrent Assets−StockThis is expressed in the form X−Y:Z.In the numerator, X−Y represents current assets minus stock.Therefore, X= current assets.And Y= stock.In the denominator, Z represents current liabilities.So, Z= current liabilities.Hence, option C correctly identifies each term.Answer:Option C: x= current assets; y= stock and z= current liabilities.