Agrapevine growing around a fence post is an example of?
a- phototropism
b-photoperiodism
c- geotropism
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.

i'd think it's paralell

but there is no

i guess you forgot putting it.