Which of the following is a synthetic auxin?

Which of the following movements in plants is due to the increased concentration of $Auxin$?

One of the commonly used plant growth hormones in tea plantations is

You are provided with a tissue to initiate differentiation in an artificial culture. Which of the following pairs of hormones would you add to the medium to induce the development of shoots and roots?

Which of the following plant hormones prevents the premature falling of fruits?

$2, 4-D$ is a