Recommending an integration with the marketing platform that creates leads in Salesforce is the best way to meet the requirement of handing off qualified prospects to the sales team. An integration is a connection between two or more systems that allows data exchange and synchronization. A lead is a record that represents a potential customer who has shown interest in a product or service. By integrating the marketing platform with Salesforce, the marketing team can automatically create leads in Salesforce when they qualify prospects based on their criteria, such as score, behavior, demographics, etc. This way, the sales team can access and follow up with the leads in Salesforce without having to manually enter them.

Explanation
This solution will meet the requirement by allowing sales reps to contact and measure the return on investment (ROI) of the purchased list. Creating a Campaign will allow sales reps to track and manage marketing efforts for a specific audience or goal. Importing the list as Leads will allow sales reps to capture information about potential customers and qualify them based on their interest and readiness. Adding them to the Campaign will allow sales reps to associate Leads with a specific marketing activity and track their responses and conversions4

Explanation/Reference:
Reference: https://help.salesforce.com/articleView?
id=brand_your_org_in_lightning_experience.htm&type=5