The correct answer is C. The spread of bacteria or pathogens from one tool, food item, or surface to another.

Reference:

Cross-contamination occurs when pathogens - microorganisms like bacteria that can cause disease, are transferred from one food product or surface to another, potentially resulting in foodborne illness. There are several ways this could happen:

• Contaminated ingredients are added to food that receives no additional cooking.
• Ready-to-eat food comes into contact with a contaminated surface.
• A contaminated food touches, or drips fluid, onto a cooked or ready-to-eat food.
• A food handler touches a contaminated food and then touches a ready-to-eat food.
• A contaminated wiping cloth touches food-contact surface.

Pathogens can transfer easily, spread from food or unwashed hands to prep areas, equipment, utensils, or other food. This can occur throughout any point of the flow of food handling - the path that food takes through your operation. This includes steps from receiving to storing, to prepping, cooking, holding, serving, etc. Knowing how and where cross-contamination can happen is half the battle. Master this knowledge and cross-contamination becomes much easier to prevent.