Analyze the following campaign scenarios and determine which ones exhibit the readiness metrics for scaling:
- Scenario I: A fashion retail campaign shows a steady increase in conversion rate from 2% to 3.5% over four months, with a consistent ad spend.
- Scenario II: An online education platform has a high engagement rate on its video ads but sees a CTR that's below the industry average, despite increased ad spending.
- Scenario III: A health and wellness app experiences a surge in unique visitors, along with an ad frequency is well above the recommended benchmarks.
- Scenario IV: A tech gadget campaign maintains a stable engagement rate and CTR, with a slight decrease in CPA over the past quarter.
Select the scenarios that show readiness for campaign scaling: