Limitation of ecological pyramid is/are:-

Question

$\begin{array}{1 1}(a)\;\text{It does not take into account the same species belonging two or more trophic levels}\\(b)\;\text{It assumes a simple food chain,it does not accommodate food web}\\(c)\;\text{Saprophytes are not given any place}\\(d)\;\text{All of the above}\end{array}$