Exam CIPP-E topic 1 question 180 discussion

SCENARIO -
Please use the following to answer the next question:
Sandy recently joined Market4U, an advertising technology company founded in 2016, as their VP of Privacy and Data Governance. Through her first initiative in conducting a data inventory, Sandy learned that Market4U maintains a list of 19 million global contacts that were collected throughout the course of Market4U’s existence. Knowing the risk of having such a large amount of data, Sandy wanted to purge all contacts that were entered into Market4U’s systems prior to May 2018, unless such contacts had a more recent interaction with Market4U content. However, Dan, the VP of Sales, informed Sandy that all of the contacts provide useful information regarding successful marketing campaigns and trends in industry verticals for Market4U’s clients.
Dan also informed Sandy that he had wanted to focus on gaining more customers within the sports and entertainment industry. To assist with this behavior, Market4U’s marketing team decided to add several new fields to Market4U’s website forms, including forms for downloading white papers, creating accounts to participate in Market4U’s forum, and attending events. Such fields include birth date and salary.
What is the best way that Sandy can gain the insights that Dan seeks while still minimizing risks for Market4U?