問題文
A campaign's stated goal is to increase online purchases. When judging the campaign's success, which metric carries the most relative value for that goal?
選択肢
- Open rate, because a high open rate always means high revenue
- Unsubscribe rate, because fewer unsubscribes proves more purchases
- Conversion rate, because it reflects how many recipients completed a purchase
- The total number of emails sent, regardless of the outcome