In a positive phototropic response of a coleoptile, the region of greatest curvature is brought about by the

A.

movement of auxins away from the region of curvature

B.

even distribution of auxins in all parts of the coleoptile

C.

inhibition of growth by auxins in the region f smaller curvature

D.

concentration of auxins in the region of curvature

E.

absence of auxins in the coleoptile

Correct answer is D

No explanation has been provided for this answer.