The answer is
D- thigmotropism
Tropism is plant growth in a response to a stimulus.
Through the process of elimination:
A - phototropism is plant growth in a response to light.
B - Photoperiodism is an organism reaction to the lengths of days and nights.
C - Gravitropism is plant growth in a response to gravity.
D - Thigmotropism is plant growth in a response to contact
Since
a grapevine makes a contact with a fence, this is an example of thigmotropism.
