Answer:
To get you to comply, she may use: b. a sanction
Step-by-step explanation:
In sociology, sanctions refer to any action or expression indicating approval or disapproval of somebody else's behavior and intended to ensure compliance with social norms. They are forms of social control, and can be positive (when they reward accepted behavior) or negative (when they punish unaccepted behavior). Therefore, to get you to use a full-length dress at her wedding, your friend may use sanction, more specifically, negative action to discourage your nonconformity to the norm.