Under what circumstances might the “soft opt-in” rule apply in relation to direct marketing?

[answerhappygod]

Under what circumstances might the “soft opt-in” rule apply in relation to direct marketing?

A. When an individual has not consented to the marketing.
B. When an individual’s details are obtained from their inquiries about buying a product.
C. Where an individual’s details have been obtained from a bought-in marketing list.
D. Where an individual is given the ability to unsubscribe from marketing emails sent to him.