The correct answer is option 1: acetic acid. Vinegar is primarily composed of acetic acid, which is a weak acid. Acetic acid is responsible for the sour taste and pungent smell of vinegar. It is produced through the fermentation process of ethanol by acetic acid bacteria.

Option 2, ascorbic acid, is also known as vitamin C and is commonly found in fruits and vegetables. It is not the acid present in vinegar.

Option 3, citric acid, is a common acid found in citrus fruits like lemons and oranges. While citric acid is used as a preservative and flavor enhancer in food and beverages, it is not the main acid present in vinegar.

Option 4, tartaric acid, is a naturally occurring acid found in grapes and tamarind. It is often used as a flavoring agent in food preparation but is not the primary acid in vinegar.

In conclusion, the correct acid present in vinegar is acetic acid (option 1).