Which of the following is not a naturally occurring plant hormone?

Select an appropriate plant hormone responsible for apical dominance from the following.

Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth,flowering,and rooting. Write a line to explain the meaning of the following terms related to auxins:
$(a)$ Auxin precursors
$(b)$ Antiauxins
$(c)$ Synthetic auxins

Most of the information regarding auxins has been obtained from

The number of auxins isolated from Phaseolus vulgaris is

Which of the following is an auxin?