The correct answer is: C. dollar invested
The dollar invested is the amount of money that is put into an investment. The return percentage is the amount of money that is earned on the investment, expressed as a percentage of the dollar invested. The dollar received is the amount of money that is received from the investment.
To calculate the return percentage, you subtract the dollar invested from the dollar received and then divide the result by the dollar invested. For example, if you invest $100 and receive $110, your return percentage is 10%.
The dollar invested is used to calculate the return percentage because it is the amount of money that is at risk. The return percentage is a measure of the risk-adjusted return on an investment.