This is such a bad question.
If you go with Customer Insights, sure it would work but the data is being loaded to the CI environment and not necessarily the environment they are referring to. If you go with the Excel Online Connector, they never said in the question what type of document they are referring to, could be word, PDF or anything really. But for argument sake let's assume Excel, You could use the connector to fetch the records and a series of actions to handle the upsert. Then there is the marketing option, sure you could map the online fields from their site directly to the DB, but the question make no mention of the use of a Dataverse.
For this one I am going to have to go with Excel Online Connector since this is the online option that allows me to fetch and post the data just about anywhere where an API is available.