Correct Answer: D
Explanation:
Sol. 2, 4-Dichlorophenoxyacetic acid (usually referred to by its abbreviation, 2, 4-D) is a common systemic herbicide used in the control of broadleaf weeds. It is one of the most widely used herbicides in the world. 2, 4-D is synthetic auxin (plant hormone) and it is often used in laboratories for plant research and as a supplement in plant cell culture media such as MS medium.