A customer wants to try a new privacy-centric media strategy and is looking for a way to test effectiveness. Which test would help them accomplish this?

To test the effectiveness of a new media strategy, a "heavy-up" test is appropriate. This involves significantly increasing the budget for the new strategy in a specific treatment group, allowing for a clear comparison against a control group that maintains the existing strategy or no strategy. This amplified investment helps isolate the impact of the new approach. "Go-dark" tests measure the impact of removing media, not introducing a new strategy. The "5% Treatment" is for gradual budget increases, which might not be sufficient to clearly demonstrate the effectiveness of a new strategy. "Holdback" tests are used to measure the incremental impact of a specific campaign by withholding it from a portion of the audience, which isn't the primary goal when testing a new overall strategy.