Answer: B. greenhouse technology
Explanation:
Greenhouse technology is the technology which can be used to grow and cultivate the crops in closed glass house. This will trap the sunlight and allow to grow the crops in cold regions of the world. As the plants are remained protected from the external environment they will remain protected against the activity of the harmful pests.
Greenhouse will be the correct option to grow more apple trees as this technology will provide high quality apples, in large number due to increase in resistance with the pests.