Forensic DNA Fingerprinting Often Involves Recovery of Minute Quantities of DNA

Forensic DNA fingerprinting often involves recovery of minute quantities of DNA from a crime scene.What is a concern in analyzing this DNA?

A) There is seldom enough DNA to allow PCR amplification.
B) Even with these tiny amounts of DNA,there may be too much DNA for efficient PCR.
C) Suspects may not agree to provide a sample of their DNA.
D) It is critical to avoid the introduction of contaminating human DNA unrelated to the crime.
E) Restriction enzymes may not work efficiently on the PCR-amplified DNA.