A food rule:-

Question

$\begin{array}{1 1}(a)\;\text{Increases variety of food at each trophic level}\\(b)\;\text{Balances the inter relationships amongst organisms}\\(c)\;\text{Decreases variety of food ,but increases qty.of food at each trophic level}\\(d)\;\text{Increases variety as well as quantity of food at each trophic level}\end{array}$