The correct answer is option 3 - statement 3 is correct.

Let`s examine each statement:

1. Statement 1: It is an antiseptic solution. - This statement is true. Tincture of Iodine is indeed an antiseptic solution that is commonly used to clean wounds and prevent infection. It helps to kill bacteria and other microorganisms.

2. Statement 2: Iodine is kept in an alcohol-water mixture. - This statement is incorrect. Tincture of Iodine is made by dissolving iodine crystals in a mixture of alcohol and water. It is not stored in this mixture.

3. Statement 3: The concentration of iodine is very low. - This statement is true. Tincture of Iodine usually contains a low concentration of iodine, typically about 2-7%. This concentration is sufficient for its antiseptic properties.

Based on the analysis, only statement 3 is correct. So, the correct answer is 3 - only statement 3 is true.