What characterizes a "contact fungicide"?

A contact fungicide is characterized by its mode of action, which involves being applied directly to the surfaces of leaves and stems without being absorbed or moved within the plant's tissues. This type of fungicide operates on a localized basis, meaning it forms a protective barrier on the plant surfaces to prevent pathogen infection. Its effectiveness depends on maintaining a coverage of the plant surfaces where the disease pathogens are likely to invade.

While contact fungicides can provide effective short-term protection against certain diseases, their lack of systemic movement within the plant means that they need to be reapplied based on environmental conditions and the specific life cycle of the pathogens. This is why option C accurately describes a contact fungicide, highlighting its application method and non-translocating nature.