AIDS is widely diagnosed by

Options

A. Widal test
B. ELISA
C. PCR
D. Chromatography.

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks about the method widely used for diagnosing AIDS.

2. **Define AIDS**: AIDS stands for Acquired Immunodeficiency Syndrome, which is a condition caused by the Human Immunodeficiency Virus (HIV).

3. **Identify the Diagnostic Tests**: The options provided are:
- A) Vidal test
- B) ELISA
- C) PCR
- D) Chromatography

4. **Evaluate Each Option**:
- **A) Vidal test**: This test is primarily used for diagnosing typhoid fever, not AIDS.
- **B) ELISA**: This stands for Enzyme-Linked Immunosorbent Assay, which is a widely used test for diagnosing AIDS by detecting antibodies against HIV.
- **C) PCR**: Polymerase Chain Reaction (PCR) is used for diagnosing various diseases, including some CNS diseases, but it is not the primary test for AIDS.
- **D) Chromatography**: This technique is used for separating mixtures and is not specifically used for diagnosing AIDS.

5. **Select the Correct Answer**: Based on the evaluations, the test that is widely used for diagnosing AIDS is the ELISA test. Therefore, the correct answer is option B.

6. **Conclusion**: The widely used test for diagnosing AIDS is the ELISA test.

**Final Answer**: B) ELISA

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