Answer:
(D). Ammonification.
Explanation:
Composting involves recycling of garden and kitchen waste to nutrient rich manure for plants. Ammonification can be defined as a process, by which nitrogen, present in organic compounds found in organisms' wastes is recycle by decomposing microorganisms.
It involves formation of ammonium ions (or ammonia) from organic nitrogen. As Kate is performing composting and she notices smell of ammonia, the process taking place in composting bin is ammonification.
Thus, the correct answer is option (D).
