Which of the Following Statements Concerning Koch's Postulates Is FALSE

Which of the following statements concerning Koch's postulates is FALSE?

A) Koch's postulates involve the experimental infection of susceptible hosts.
B) All of Koch's postulates must be satisfied before an organism can be shown to cause a particular disease.
C) Koch's postulates cannot be used to demonstrate the cause of all diseases.
D) The suspected pathogen may not be present in all cases of the disease being studied.
E) A suspected pathogen must be able to be grown in the laboratory.