Step 1: Understanding the Concept:
Hygiene refers to behaviors that maintain health and prevent the spread of diseases.
Step 2: Detailed Explanation:
- Washing hands, bathing, and brushing teeth remove germs (bacteria and viruses) from the body.
- Good hygiene prevents self-infection and prevents the spread of germs to friends, family, and colleagues.
- While (B) is a social benefit, the "primary" reason is always health-related.
Step 3: Final Answer:
The fundamental purpose of hygiene is health and illness prevention (C).