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 analogy presented in the question, we need to understand the relationship between the terms given.

1. **Understanding the first part of the analogy:**
- The first part of the analogy is "Heat treatment: Sterilisation."
- Heat treatment is a process used to kill or inactivate harmful microorganisms in various substances, leading to sterilisation.

2. **Understanding the second part of the analogy:**
- The second part is "Vaccination: X."
- Vaccination is a process used to stimulate the immune system to develop protection against specific diseases.

3. **Identifying the relationship:**
- In the first part, heat treatment leads to sterilisation. Similarly, vaccination leads to a specific outcome related to the immune system.

4. **Finding the correct term for X:**
- The outcome of vaccination is the development of immunity against diseases. This process is known as immunization.
- Therefore, we can conclude that "Vaccination: Immunization."

5. **Final Answer:**
- X refers to **Immunization**.