21.) A start-up has a required payback period of 3 years for all of its projects. Currently, the start-up is analyzing two independent projects. Project A has an expected payback period of 2.8. Project B has an expected payback period of 2.6 years. Which projects should be accepted based on the payback decision rule? a. Project A only b. Project B only c. Both A and B d. Neither A nor B e. Answer cannot be determined based on the information given