A. Mastitis
B. Rinderpest
C. Trypanosomiasis
D. Tuberculosis
Correct Answer: Option A
A. Mastitis
Explanation
Mastitis in dairy cows is caused by udder infections, usually resulting from bacteria introduced either during the milking process or from environmental contact. Milk-secreting tissues and various ducts throughout the udder can be damaged by bacterial toxins, and sometimes permanent damage to the udder occurs.