The probability is 0.10 that the machine currently in use for filling cereal boxes with HappyOs cereal will underfill a box. Which of the following statements is TRUE regarding boxes randomly sampled from the filling process?

a. In a sample of 50 boxes, it would be impossible for all 50 boxes to be underfilled
b. In a sample of 50 boxes, exactly 5 will be underfilled
c. In a very large sample of boxes, you are certain to get at least one underfilled box
d. The proportion of underfilled boxes will get closer to 0.10 as the number of sampled boxes increases.