If an association is found between the incidence of a disease and a certain genetically determined characteristic:
a. The disease is clearly genetic in origin
b. Genetic factors are at least implicated in all cases of the disease
c. Genetic factors are implicated in at least some cases of the disease
d. A role for environmental factors is excluded
e. Expression of the disease is likely to be unavoidable
Answer: c. Genetic factors are implicated in at least some cases of the disease