The correct option is
B A →iii; B → i; C→ iv; D → ii
Plague is a class of dangerous, life-threatening and infectious disease caused by the bacterium Yersinia pestis. The bacterium is mainly found in animals like rodents (rats). The insects that feed on the blood of these animals transmit this disease. This disease is also called black plague, as the black rats are the main carriers of the pathogen. It can also spread from person to person through air or by any other means of contact. It is an infection in the lymph nodes of the body. The lymph nodes get swollen, fingers start turning blue/ black and patients develop severe pain with fever, chills, weakness and headache.
Diphtheria is a communicable bacterial infectious disease caused by Corynebacterium diphtheriae, which causes inflammation of the mucous membranes, forming a false membrane in the throat creating problems while swallowing food and during breathing, resulting in slurred speech. The person also experiences symptoms like common cold, greyish thick covering on the tonsils and throat, fever, swollen neck, sore throat etc. The bacterial toxin released can damage the nerves. This disease spreads easily from one person to another but can be prevented by administration of vaccines.
Typhoid is an infectious bacterial disease caused by Salmonella typhi that mainly spreads through contaminated food or water. The common symptoms seen are continued high fever, headache, stomachache, constipation, loss of appetite, perforation in the intestine and ulcers in severe cases. The bacteria enters the human body through the contaminated water and food, and from here it enters the intestinal cells of the human body. Later, it enters the bloodstream, reaches the lymphatic system and destroys it. The bacteria is mainly carried by the WBCs present in the liver and in the bone marrow.
Tuberculosis (TB) is a highly contagious bacterial disease caused by Mycobacterium tuberculosis. It primarily affects the lungs, but if left untreated, it might spread to different parts of the body. It is an airborne disease, which can be acquired from close contact by an infected person.