Odd One Out — Among the diseases Tuberculosis, Smallpox, Cholera, and Typhoid, identify the one that does not belong to the same broad class of causative agents (bacterial vs viral) and justify your choice.

Introduction / Context:
Classification items in verbal reasoning often rely on a shared scientific property. Here we consider whether each disease is primarily caused by a bacterium or a virus and use that distinction to isolate the outlier.

Given Data / Assumptions:

• Tuberculosis: caused by Mycobacterium tuberculosis (bacterium).
• Cholera: caused by Vibrio cholerae (bacterium).
• Typhoid: caused by Salmonella Typhi (bacterium).
• Smallpox: caused by Variola virus (virus).

Concept / Approach:
Group items by causative agent. If three are bacterial diseases and one is viral, the viral disease is the odd one out.

Step-by-Step Solution:
Check Tuberculosis → bacterial.Check Cholera → bacterial.Check Typhoid → bacterial.Check Smallpox → viral.Therefore, Smallpox stands apart by etiology.

Verification / Alternative check:
Another check is eradication status: Smallpox was globally eradicated via vaccination; the other three remain public health concerns. This independent trait also singles out Smallpox.

Why Other Options Are Wrong:

• Tuberculosis: bacterial; aligns with the majority.
• Cholera: bacterial; aligns with the majority.
• Typhoid: bacterial; aligns with the majority.

Common Pitfalls:
Confusing “prevalence” with classification. Even though smallpox is eradicated, its key distinguishing feature here is viral causation, not prevalence.

Final Answer:
Small pox