The correct answer is: B. Interest rate.
Interest rate is the ratio of interest payment to the principal for a given unit of time and usually expressed as a percentage of the principal.
Return of investment (ROI) is the ratio of the profit or loss from an investment relative to the amount of money invested.
Yield is the amount of money an investor expects to receive from a particular investment, typically expressed as a percentage of the amount invested.
Rate of return is the amount of profit or loss an investor makes on an investment relative to the amount of money invested.