The correct answer is - b) parasitism.
The kudzu is a plant that has adapted to get stuck to the other plants, usually trees and bigger shrubs, and get nutrients and water through them. In this way, the kudzu shows elements of parasitism, as it is using a host plant in order to satisfy its needs.
The native plants and shrubs will have a big problem with an introduction of the kudzu in their environment. They will not have a defense mechanism, and the kudzu will spread out very quickly and suck the nutrients and water out of them, hindering their growth and even killing them over the coarse of longer period of time.
This would be a prime example of parasitic relationship between the kudzu and the native plants.