Final answer:
The researcher should use an observational study that collects information about eye color of people with skin cancer to examine the relationship between eye color and the incidence of skin cancer.
Step-by-step explanation:
The answer to this question is A) Use an observational study that collects information about eye color of people with skin cancer.
An observational study is the most appropriate approach to examine the relationship between eye color and the incidence of skin cancer. In this study, the researcher would collect information on the eye color of individuals who have been diagnosed with skin cancer. By comparing the eye color distribution among individuals with skin cancer to the general population, the researcher can assess if there is any association between eye color and skin cancer incidence.
For example, the researcher may collect eye color data from a sample of individuals diagnosed with skin cancer and compare it to a representative sample of the general population. If the proportion of individuals with a specific eye color is significantly different between these two groups, it may suggest a relationship between eye color and skin cancer.