Companies O and P each have the same number of employees who work the same number of hours per week. According to records maintained by each company, the employees of Company O had fewer job-related accidents last year than did the employees of Company P. Therefore, employees of Company O are less likely to have job-related accidents than are employees of Company P.

Which of the following, if true, would most weaken the conclusion above?

【选项】The majority of job-related accidents at Company O involved a single machine.