The ring worm is one of the most common infectious disease caused by :

The correct answer is Option (3) → Fungi

Option (3) Fungi — Correct. Of the options, only fungi cause ringworm; NCERT names three fungal genera behind it.

NCERT Extract:
Common Diseases in Humans – “… Many fungi belonging to the genera Microsporum, Trichophyton and Epidermophyton are responsible for ringworms which is one of the most common infectious diseases in man. Appearance of dry, scaly lesions on various parts of the body such as skin, nails and scalp (Figure 7.3) are the main symptoms of the disease. These lesions are accompanied by intense itching.”