The correct answer is: D. Either of the above.
A pure ratio is a comparison of two quantities without any units. For example, the ratio of the price of a stock to its earnings per share is a pure ratio. A percentage is a pure ratio multiplied by 100. For example, the price-to-earnings ratio of a stock is typically expressed as a percentage. A rate is a ratio of two quantities with different units. For example, the interest rate on a loan is a ratio of the amount of interest to be paid to the amount of money borrowed. Time is a quantity that can be used to express the relationship between two financial variables. For example, the maturity of a bond is the length of time until the bond must be repaid.
In conclusion, the relationship between two financial variables can be expressed in a pure ratio, a percentage, a rate, or time.