The correct answer is: A. Fungi
Ringworm is a fungal infection of the skin. It can cause a round, red, scaly rash on the skin. Ringworm is contagious and can be spread from person to person through contact with the infected skin or through contact with objects that have been contaminated with the fungus.
Bacteria are single-celled organisms that can cause a variety of diseases, including pneumonia, strep throat, and food poisoning. Bacteria are not the cause of ringworm.
Viruses are tiny, infectious particles that can cause a variety of diseases, including the common cold, the flu, and AIDS. Viruses are not the cause of ringworm.
Flies are insects that can transmit diseases, such as malaria and yellow fever. Flies are not the cause of ringworm.