Study the given correlation.
Heat treatment: Sterilisation :: Vaccination : X
Here, X refers to ______

Options

A. Pasteurisation
B. Immunisation
C. Fertilisation
D. Inoculation

Explanation

To solve the correlation given in the question, we need to analyze the relationship between the terms provided.

1. **Understanding the First Pair: Heat Treatment and Sterilization**
- Heat treatment is a method used to sterilize equipment and materials by killing or inactivating all forms of microbial life. This process ensures that the items are free from any pathogens or contaminants.
- Therefore, we can conclude that heat treatment is a technique used for sterilization.

2. **Understanding the Second Pair: Vaccination and X**
- Vaccination is a process used to stimulate the immune system to develop protection against specific diseases. It introduces a harmless component of a pathogen (like a protein or a weakened form of the pathogen) to the body, prompting the immune system to respond.
- The outcome of vaccination is the development of immunity against the disease for which the vaccine was administered.

3. **Finding the Relationship for X**
- Since heat treatment leads to sterilization, we need to find a term that relates to vaccination in a similar way.
- The process that results from vaccination is known as immunization. Immunization is the state of being protected against a disease, which is the direct result of vaccination.

4. **Conclusion**
- Therefore, in the analogy: Heat treatment is to sterilization as vaccination is to immunization.
- Thus, X refers to **immunization**.

**Final Answer: Immunization**

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