Correct Option: C

2, 4-Dichlorophenoxy acetic acid is used for causing defoliation of forest trees. 2, 4-D or 2, 4 Dichlorophenoxy acetic acid is an auxin hormone. It stimulates the growth activities of the cells of the root due to which roots get destroyed and thus plants finally destroys. 2, 4-D is used as a defoliant for broad leaved dicots.