The correct option is B Grafting
In grafting, we join two plants to each other. The upper part of the graft is called scion that forms the top portion of the plant, and lower part which we call understock makes roots or part of the stem. Grafting is usually joining of only two plants but it may be a combination of several. If we join a third plant between two plants then it forms the trunk or a portion of it. This third plant is called an interstem.