Dr F. Went noted that if coleoptile tips were removed and placed on agar for one hour, the agar would produce a bending when placed on one side of freshly- cut coleoptile stumps. Of what significance is this experiment ?

Question

( A ) It supports the hypothesis that IAA is auxin.
( B ) It demonstrated polar movements of auxins
( C ) It is the basis for quantitative determination of small amounts of growth- promoting substances.
( D ) It made possible the isolation and exact identification of auxin.