Answer:
a company employee with first-hand knowledge of the processing plant.
Step-by-step explanation:
Employees working in an organization would normally not want to give information to the press about any alleged violations made by the company for fear of being dismissed or fired.
As in the above scenario, the journalist who is investigating the alleged chemical violation would not mention 'janitor' as his source because that is too direct and he could be identified by his company as the person who share the information to the press.
As a rule, press group like Reuters would always have hand book that guides them on any investigation particularly when the respondent wants remain anonymous for fear of being sanctioned.
Therefore, for the respondent, I.e 'janitor' to remain anonymous, the journalist must quote his or her source as " a company employee with first-hand knowledge of the processing plant.