Email Subject Line A/B Test Matrix

Create subject line A/B test matrix:

Campaign Type: {{campaign_type}}
Audience Segment: {{segment}}
Primary Message: {{message}}
Company/Product: {{product}}
Offer/CTA: {{offer}}

Generate 10 subject line pairs (A vs. B) across these dimensions:
1. Curiosity-driven vs. Benefit-driven
2. Data/number-based vs. Narrative
3. Urgency vs. No urgency
4. Personalization (name) vs. Generic
5. Question vs. Statement

For each pair provide:
- Both subject lines
- Predicted performance (open rate estimate)
- Hypothesis (why B might outperform A)
- Character count & mobile preview
- Recommendation