The annual rate of coal production in the US (in billions of tons per year) is given by the function a(t), and the total amount of coal produced (in billion tons) since 1900 is given by c(t), where t represents years since 1900. If the total amount of coal produced is 3 billion tons higher in 1960 than it was in 1915, which of the following mathematical equations must be true? Select all of the following that are correct. C A. % [165 c'(t)dt = 3 C B. a(60) a(15) = 3 c. C(60) c(15) = 3 C p. a(60) 1105) = 3 C E. ffs" c(t)dt = 3 C F. c'(60) c'(15)= 3 C e. if? a(t)dt = 3 60 i H' 45 15 c'(t) dt = 3 C I. None of the above are true