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