The Problem(s) with Using Sludge as a Fertilizer Is/are the

The problem(s) with using sludge as a fertilizer is/are the

A) presence of heavy metals and similar pollutants AND inhibitory effect it has on plant growth.
B) presence of heavy metals and similar pollutants AND presence of pathogenic organisms and viruses.
C) presence of pathogenic organisms and viruses AND inhibitory effect it has on plant growth.
D) inhibitory effect it has on plant growth AND stimulatory effect it has on methane production.
E) stimulatory effect it has on methane production AND presence of pathogenic organisms and viruses.