Which of the following is a pair of viral disease ?

AIDS, common cold.

The correct answer is Option (4) -AIDS, Common cold

Explanation:

• Common cold : The common cold is usually caused by viruses, primarily rhinoviruses.
• AIDS (Acquired Immunodeficiency Syndrome): It is caused by the human immunodeficiency virus (HIV), which attacks the immune system, specifically targeting CD4 cells (T-helper cells). HIV weakens the immune system, making individuals more susceptible to infections and diseases.

However, the other options mentioned (Plague, pneumonia; Typhoid, common cold; AIDS, malaria ) do not present pairs of viral diseases. Plague is caused by the bacterium Yersinia pestis, pneumonia can be caused by various pathogens including bacteria, viruses, and fungi, and Typhoid is caused by the bacterium Salmonella typhi While Malaria is caused by a protozoan parasite Plasmodium.