18. What is meant by the term 'cost of capital'? O a. The rate of return that a company has to offer purchasers of bonds to induce them to buy O b. The rate of return that a company has to offer shareholders as dividends Oc. The rate of return that a company has to offer finance providers to induce them to buy and hold financial security. O d. The rate of return that a company has to pay for its capital investments