Final answer:
Encouraging and offering help to a student refusing to work is the best approach, using informal positive sanctions rather than negative ones or ignoring the issue.
Step-by-step explanation:
The most appropriate response to a student who is refusing to work on an assignment is to encourage and offer help. This approach aligns with informal positive sanctions, which involve using positive reinforcement to guide behavior. Punishment, such as formal negative sanctions, can have a detrimental effect on motivation, while ignoring the behavior may not address any underlying issues. Moving the student to a different class does not solve the problem and is not a constructive solution.
Consider the scenario where an instructor threatens to fail the entire class without any specific cause; this represents an extreme form of formal negative sanction, which is likely to elicit a negative response from students and can damage the learning environment. Instead, providing encouragement and support helps to create a positive classroom atmosphere, encouraging students to take on challenges and seek assistance when needed.