What is a zone fire model?

What is a zone fire model?
 
  A) Replications of a fire scenario that create a structure or item with a scaled-down geometric dimension and/or other variables
  B) Replications of a fire scenario that create a structure or item with similar geometric dimensions and attempt to reproduce fire phenomena
  C) A type of modeling that typically separates the compartment into two zones, commonly referred to as the upper (hot) zone and lower (cool) zone
  D) The use of computers to synthesize lengthy, time-dependent algorithms through a variety of software and model types