Evan takes 100 milligrams of medicine. the  amount  of medicine in his bloodstream  decreases  by 0.4 milligram each  minute  for a number of  minutes,  m, after that. he writes the  expression  100 – 0.4m  to find the  amount  of medicine in his bloodstream after  m  minutes. which  statement  about his  expression  is true? a. it is the product of the initial amount and the amount of decrease each minute,  m. b.it is the difference between the initial amount and the amount of decrease after  m  minutes. c.it is the product of the initial amount and the amount of decrease after  m  minutes. d.it is the difference between the initial amount and the number of minutes,  m.