Explanation:

- Vinegar is primarily composed of Acetic acid, which gives it its distinct sour taste and pungent smell. It is widely used in cooking and cleaning.

- Correct Answer: Option 3 - Acetic acid

- Tartaric acid is found in many plants, and it's often derived from grapes. It's commonly used in baking powders and as a food additive.

- Not relevant to vinegar's composition.

- Nitric acid is a strong acid used in fertilizers and explosives.

- Not related to vinegar.

- Citric acid is found in citrus fruits such as lemons and limes. It's often used as a preservative and acidifier.

- Not the acid found in vinegar.