Final answer:
An organism capable of causing disease in immunocompromised individuals but not typically in healthy people is termed an 'opportunistic' pathogen.
Step-by-step explanation:
The term for a nonpathogenic organism that is capable of producing disease in an immunocompromised patient is C. Opportunistic. Opportunistic pathogens can only cause disease in circumstances where the host's defenses are compromised, such as situations involving immune system impairment or when protective barriers are breached.
As an example, Staphylococcus epidermidis often exists harmlessly on the skin but can cause serious infections if it enters the body through medical interventions like catheter insertion. This contrasts with primary pathogens, like enterohemorrhagic E. coli (EHEC), which produce toxins and cause disease even in individuals with healthy immune systems.