What are the three factors that determine the severity of pollutant?

Question

$\begin{array}{1 1} (a)\;\text{Air,Water,Land} \\ (b)\; \text{fertilizers,minerals,nutrients} \\ (c)\; \text{its chemical nature, the concentration and the persistence} \\ (d)\; \text{temperature changes ,Water content and amount of rainfall} \end{array}$