A manufacturer of light bulbs wants to produce bulbs that last about 600 hours but, of course, some bulbs burn out faster than others, Let F(t) be the fraction of the company's bulbs that bum out before { hours. F(t) lies between 0 and 1. Let r(t) = F(t) . What is the value of for(t)dt Oa. for(t)dt = 2 Ob. for(t)dt = 0 O c. divergent Od. for(t)dt = 1 Oe. for(t) dt = 600