Assertion: AIDS can be diagnosed immediately after HIV infection by ELISA test.
Reason: Large number of antibodies are formed spontaneously.

Options

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

Answer

To analyze the given assertion and reason, we will break down the statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "AIDS can be diagnosed immediately after HIV infection by ELISA test."
- **Explanation**: The ELISA test is a widely used method for detecting antibodies against HIV in a person's blood. However, it is important to note that antibodies do not appear immediately after infection.

2. **Understanding the Reason**: The reason states that "Large number of antibodies are formed spontaneously."
- **Explanation**: The formation of antibodies in response to an HIV infection does not occur instantaneously. It typically takes time for the immune system to recognize the virus and produce antibodies.

3. **Timing of Antibody Formation**: After HIV infection, it usually takes about 4 to 6 weeks for the body to produce detectable levels of antibodies against HIV. This period is known as the "window period."
- **Conclusion**: Therefore, the assertion that AIDS can be diagnosed immediately after HIV infection is incorrect.

4. **Evaluating the Truth of Both Statements**:
- The assertion is false because immediate diagnosis is not possible.
- The reason is also misleading because it implies that antibodies are formed instantly, which is not the case.

5. **Final Evaluation**: Since the assertion is false and the reason is misleading, we conclude that both statements are not true.

### Final Answer:
- Both the assertion and reason are false.