Which of the Following Is Not a Contentious Case of Injury

Which of the following is not a contentious case of injury or illness covered under workers compensation?

A) Injuries resulting from faulty design of the machinery used in the production floor.
B) An employee killed by a stranger when the employee is on a vacation.
C) Injuries occurring when the employee is "on the road," especially if the trip began from  the employee's home.
D) Chronic illnesses such as lung disease, especially if contributing factors include  workplace hazards (e.g., dust) in combination with personal behavior (e.g., smoking) .