A common disease affecting cattle in Karnataka:

Foot-and-mouth disease
Brucellosis
Anthrax
Rabies

The correct answer is A) Foot-and-mouth disease.

Foot-and-mouth disease (FMD) is a highly contagious viral disease that affects cloven-hoofed animals, including cattle, pigs, sheep, goats, and deer. It is characterized by fever, lameness, and blisters on the mouth and feet. FMD is a serious disease that can cause significant economic losses to the livestock industry.

Brucellosis is a bacterial disease that can affect a variety of animals, including cattle, pigs, sheep, goats, and dogs. It is characterized by fever, abortion, and arthritis. Brucellosis is a zoonotic disease, meaning that it can be transmitted from animals to humans.

Anthrax is a bacterial disease that can affect a variety of animals, including cattle, pigs, sheep, goats, and horses. It is characterized by fever, swelling, and hemorrhage. Anthrax is a zoonotic disease, meaning that it can be transmitted from animals to humans.

Rabies is a viral disease that affects the central nervous system of mammals. It is characterized by fever, anxiety, and aggression. Rabies is a zoonotic disease, meaning that it can be transmitted from animals to humans.

Foot-and-mouth disease is the most common disease affecting cattle in Karnataka. It is a highly contagious viral disease that can cause significant economic losses to the livestock industry.