Assertion:Medulla contains centres which control respiration, cardiovascular reflexes and gastric secretions.
Reason:Medulla contains several neurosecretory cells which secrete hormones.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that the medulla oblongata contains centers that control respiration, cardiovascular reflexes, and gastric secretions. This is a true statement. The medulla is a critical part of the brainstem that regulates these vital functions.

2. **Understanding the Reason**: The reason provided is that the medulla contains several neurosecretory cells that secrete hormones. This statement is incorrect. While the medulla does have important functions, the neurosecretory cells that produce hormones are primarily located in the hypothalamus, which is part of the diencephalon.

3. **Evaluating the Relationship**: Since the assertion is true and the reason is false, we conclude that the assertion is correct but the reason does not support it.

4. **Final Conclusion**: Based on the evaluation, the answer to the question is that the assertion is true, but the reason is false. Therefore, the correct option is C: Assertion is true, but reason is false.