Which of the following statements is correct ?

Options

A. Hepatitis B virus (HBV) can be transmitted through blood transfusion, sexual contact, saliva, tears, intravenous drug abuse, tatooing, ear and nose pierceing, sharing of rozors etc
B. Hepatitis B virus vaccine is the second generation vaccine produced from transgenic yeast by recombinant DNA technology
C. Heptitis B virus vaccine is the first commercially available human vaccine produced by genetic engineering
D. all of these

Answer

To solve the question "Which of the following statements is correct?" regarding Hepatitis B virus and its vaccine, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Hepatitis B Virus Transmission**:
- The first statement mentions that Hepatitis B virus can be transmitted through various means such as blood transfusion, sexual contact, saliva, tears, intravenous drug abuse, tattooing, ear and nose piercing, and sharing razors.
- **Analysis**: This statement is correct as Hepatitis B can indeed be transmitted through all these routes.

2. **Evaluating the Vaccine Production**:
- The second statement claims that the Hepatitis B virus vaccine is a second-generation vaccine produced from transgenic yeast by recombinant DNA (rDNA) technology.
- **Analysis**: This statement is also correct. The vaccine is produced using rDNA technology, which involves genetically modifying yeast to produce the vaccine components.

3. **First Commercially Available Vaccine**:
- The third statement states that the Hepatitis B virus vaccine is the first commercially available human vaccine produced by genetic engineering.
- **Analysis**: This statement is accurate. The Hepatitis B vaccine was indeed the first vaccine produced using genetic engineering techniques, becoming available in 1986 under the name Recombivax HB.

4. **Conclusion**:
- The last option states "All of this," which implies that all the previous statements are correct.
- **Final Analysis**: Since all three statements have been verified as correct, the answer to the question is option D: "All of this."

### Final Answer:
The correct answer is **D: All of this**.

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