Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human Immunodeficiency Virus (HIV). Among the options given, which route correctly describes a common way by which HIV infection is transmitted from one person to another?

Introduction / Context:
Acquired Immunodeficiency Syndrome (AIDS) is a serious condition caused by infection with the Human Immunodeficiency Virus (HIV). HIV attacks the immune system, especially CD4 T cells, making the body vulnerable to many opportunistic infections. Understanding the main modes of transmission of HIV is essential for both public health and individual prevention. This question focuses on identifying a correct route of HIV transmission from among several possibilities.

Given Data / Assumptions:

• The disease is AIDS, caused by HIV.
• We must identify how the virus is commonly transmitted between individuals.
• Options mention contaminated food, blood transfusion, polluted air, handshakes, and shared meals.
• We assume basic knowledge of safe and unsafe practices regarding HIV.

Concept / Approach:
HIV is primarily transmitted through specific body fluids, such as blood, semen, vaginal secretions, rectal fluids, and breast milk, when they come into direct contact with a mucous membrane or damaged tissue, or are directly injected into the bloodstream. Common routes include unprotected sexual contact with an infected partner, transfusion of contaminated blood and blood products, sharing contaminated needles, and from infected mother to child during pregnancy, birth, or breast feeding. HIV is not transmitted by casual contact, air, or by eating ordinary food prepared by infected individuals.

Step-by-Step Solution:
Step 1: Recall the main routes of HIV transmission: unsafe sexual contact, contaminated blood transfusions, shared needles, and mother to child transmission. Step 2: Check which option among those given involves direct contact of infected blood or body fluids with the bloodstream. Step 3: Identify that transfusion of contaminated blood and blood products puts infected blood directly into another person's bloodstream. Step 4: Recognize that eating food, inhaling air, or shaking hands do not provide such direct access for HIV. Step 5: Conclude that transfusion of contaminated blood and blood products is the correct route among the options given.

Verification / Alternative check:
Many public health campaigns emphasize safe blood transfusions and blood screening to prevent HIV and other blood borne infections. Hospitals routinely test donated blood for HIV to avoid exactly this type of transmission. In contrast, there are no public health warnings about catching HIV from food, water, or handshakes, because these are not routes of transmission. Remembering such campaigns and hospital procedures confirms that contaminated blood transfusion is a recognized and important route of HIV spread.

Why Other Options Are Wrong:
Eating contaminated food and drinking polluted water: This can cause diseases like cholera, typhoid, or food poisoning but not HIV infection. Inhaling polluted air in crowded areas: Airborne transmission is relevant for diseases like tuberculosis and influenza, not for HIV. Shaking hands or casual contact with an infected person: HIV is not spread by casual physical contact such as handshakes, hugging, or sharing utensils. Sharing cooked meals from the same plate: Normal social sharing of food does not transmit HIV because the virus does not survive in cooked food and is not transmitted through saliva in ordinary contact.

Common Pitfalls:
Fear and stigma sometimes lead people to wrongly believe that HIV spreads easily by casual contact, sharing food, or breathing the same air. These misconceptions can result in discrimination against people living with HIV. Understanding that HIV requires specific high risk exposures involving blood and certain body fluids is crucial. Clear knowledge of what does not transmit HIV is just as important as knowing what does, because it helps reduce unnecessary fear and improves social support for affected individuals.

Final Answer:
Therefore, among the options listed, a common route for HIV transmission is Transfusion of contaminated blood and blood products.