Final answer:
The adult client who owns a restaurant and has a history of alcoholism is at the highest risk of developing colorectal cancer.
Step-by-step explanation:
Among the given options, the adult client who owns a restaurant and has a history of alcoholism is at the highest risk of developing colorectal cancer. Excessive alcohol consumption is one of the factors that increase the risk of colorectal cancer. Other risk factors include smoking, a diet high in animal fat and protein, and a family history of colorectal cancer. The option with the restaurant owner matches the risk factors, making it the highest-risk candidate.