Obstacle to large scale transplantation of organs is

Options

A. Insufficiency of organ donors
B. Lack of effective surgical techniques
C. Religious or ethnic consideration
D. Immunological rejection of foreign bodies

Answer

### Step-by-Step Solution:

1. **Understanding Organ Transplantation**: Organ transplantation is a medical procedure where an organ is removed from one person's body (the donor) and placed into another person's body (the recipient).

2. **Identifying the Main Obstacle**: The primary obstacle to large-scale organ transplantation is the immune response of the recipient's body. When a foreign organ is introduced, the immune system recognizes it as a foreign entity and attempts to reject it.

3. **Explaining the Immune Response**: The immune system's reaction involves various cells and antibodies that work to eliminate what it perceives as a threat. This response can lead to the failure of the transplanted organ, necessitating its removal.

4. **Mitigating the Immune Response**: To counteract this immune response, immunosuppressant drugs are administered to the recipient. These drugs help suppress the immune system, reducing the likelihood of rejection of the transplanted organ.

5. **Conclusion**: The main obstacle to large-scale organ transplantation is the immunological reaction of the recipient's body to the foreign organ. The use of immunosuppressant drugs is crucial in overcoming this barrier.

### Final Answer:
The obstacle to large-scale transplantation of organs is the immunological reaction of the recipient's body to the foreign organ.

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