Final answer:
A. Splice grafting is the technique where the stock and scion must be of equal size, which allows for the two plant segments to be joined together effectively.
Step-by-step explanation:
For which of the following are the stock and scion of equal size? The answer is a) splice. Splice grafting involves joining two plant segments of similar size. This technique is commonly used to merge two segments so that they grow as one. Unlike the splice graft, cleft grafting typically involves a larger stock and a smaller scion that is inserted into a split in the stock. In bark inlay and patch grafting, the scion is often smaller than the stock, and a piece of bark or a patch is used to connect them. Notch grafting can involve various sizes of stock and scion, but it's not defined by having equal sizes. Splice grafting is the only method that specifically requires the stock and scion to be of equal size for effective grafting.
In grafting, the process of joining together two plant parts, there are different methods to achieve the union between the stock and scion. Among the methods given in the question, the cleft technique allows for the stock and scion to be of equal size.