The principle of the time value of money basically says that O O A. because firms pay managers a great deal, managers need to use their time very effectively B . because of the principal-agent problem, investors cannot trust that money firms promise to pay in the future will ever arrive O C. money received today is more valuable than money received in the future because money in the future is more risky O D. money received today is more valuable than money received in the future because firms and individuals can invest money they have today and eam a return on that money