Final answer:
The choice of the correct final stable syllable for "addi" is likely "-tion", resulting in the word "addition", but cannot be definitively determined without additional context.
Step-by-step explanation:
The question is about identifying the correct final stable syllable to be added to the word "addi". The suffix options provided are "tion" and "sion". However, without a specific combination in the provided list that begins with "ad + di", we cannot decide which of the two suffixes would be appropriate solely based on the provided stems and suffixes. Typically, the suffix "-tion" is added to a base to form nouns indicating the action, result, or means of an action, such as "addition", where the base is "addi" and "-tion" completes the word. On the other hand, "-sion" is added to verbs to form nouns primarily when the root word ends in "d" or "se". Since the given base is "addi", the more likely correct final stable syllable to combine would be "-tion" to form "addition", but this is not explicitly confirmed without more context or specific rules in the assignment prompt.