Answer: Option (C) is the correct answer.
Explanation:
Indicators are the substances which show change in the color when added to a certain substance. An indicator helps in knowing whether the substance to which it is being added is acidic or basic.
For example, when a blue litmus is dipped into hydrochloric acid then it turns into red. Therefore, blue litmus indicates that hydrochloric acid is an acid.
Similarly, when ammonia is added to the red cabbage then the color changes from red to green. As ammonia is a basic solution therefore, when added to red cabbage the change in pH of solution will be greater than 7.
Thus, we can conclude that ammonia could be in the middle or the right test tubes since it is a weak to moderate base.