It can be inferred from paragraph 2 that part of the reason that the top of a storm cloud becomes positively charged is that A. the top of the cloud is warmer than the middle of the cloud B. the middle of the cloud is already occupied by positively charged particles C. the negatively charged ice pellets are too heavy to be carried by the updrafts that move ice crystals D. collisions between ice pellets in the top of the cloud produce mainly positively charged particles