You Take 50 ML of Small BB's and Combine Them

Multiple Choice

You take 50 mL of small BB's and combine them with of large BB's and you get a total of 90 mL of BB's of mixed size. Which of the following statements best explains this?

A) Since the density of the small BB's is less than that of the large BB's their volumes do not add directly to one another.
B) This is not possible since the Law of Conservation of Volume would be violated.
C) The total volume actually gets larger since mixing the BB's would leave additional air space because of the difference in size of the two BB sets.
D) Many of the smaller BB's are able to fit within the pockets of space that were empty within the of large BB's.