Correct option:(3)Standing state
Solution:

• Amount of all the inorganic nutrients like carbon, nitrogen, phosphorus and calcium present in soil at any given time is
  called as standing state.
• Amount of living material present in different trophic levels at a given time is called standing crop.
• Climax community is the last community in biotic succession.
• It is relatively stable and is in near equilibrium with the environment of that area.