Final answer:
The most intrusive prompt to get James to verbally request a gummy worm is telling him to say 'Gummy' before reaching for it, as it insists on a specific verbal behavior.
Step-by-step explanation:
When James is reaching for a gummy worm without using his words to express his want, there are various levels of prompts one could use to encourage verbal communication. The most intrusive prompt in this scenario would be option 2), telling James to say 'Gummy' before giving him the worm. This is considered most intrusive because it imposes a specific verbal response requirement. In contrast, asking if he wants the gummy worm involves the child in a question but does not directly impose the need to speak, moving the worm away is a nonverbal prompt, and ignoring him avoids any prompt altogether. It is important to read body language to gauge how your subject is reacting to prompts. This can inform the effectiveness of the prompt and the subject's comfort level with it.