When there is a sudden loss of blood from the body the organ which supplies blood is `:-`

Options

A. Spleen
B. Heart
C. Liver
D. Lung

Answer

### Step-by-Step Solution:

1. **Understanding Blood Loss**: When there is a sudden loss of blood from the body, it is crucial to identify which organ can compensate for this loss by supplying blood.

2. **Role of Red Blood Cells (RBCs)**: Red blood cells, which contain hemoglobin, are responsible for transporting oxygen throughout the body. The lifespan of RBCs is approximately 120 days, after which they are typically removed from circulation.

3. **Function of the Spleen**: The spleen plays a significant role in the body as it acts as a graveyard for old and damaged RBCs. It is also involved in purifying the blood by removing pathogens and dead cells.

4. **Blood Storage in the Spleen**: The spleen serves as a reservoir for blood cells. It can store blood and release it into circulation when there is a sudden loss of blood, thus helping to maintain blood volume and pressure.

5. **Exclusion of Other Organs**:
- The heart is primarily a pumping organ and does not store blood.
- The liver has multiple functions but does not serve as a primary source for supplying blood in cases of sudden loss.
- The lungs are involved in gas exchange and do not contribute to blood supply.

6. **Conclusion**: Therefore, when there is a sudden loss of blood, the organ that supplies blood is the spleen.

### Final Answer:
The organ which supplies blood during sudden loss of blood from the body is the **spleen**.

---