Answer:
Option D, products that start a new reaction are released
Step-by-step explanation:
A chain reaction is a continuous process in which the product formed as a result of a chemical/physical reaction leads to further reactions ahead. This process of one reaction generating other reaction goes on uncontrollably.
Some common example of chain reaction are as follows - a) nuclear reaction , b) reaction of chlorofluorocarbon compounds with ozone layer of atmosphere etc.
Hence, option D is correct