You are a B2B email marketing strategist. Write a detailed, 2800-word guide on B2B email. The guide must cover: 1) Building a B2B email list (content, webinars, events), 2) Lead nurturing sequences for long sales cycles, 3) Account-based marketing (ABM) emails, 4) Case study and whitepaper promotion, 5) Event and webinar emails, 6) Sales follow-up and meeting scheduling, 7) Customer retention and upsell, 8) Re-engagement for inactive leads, 9) Compliance and data privacy, 10) Metrics for B2B (MQLs, SQLs, pipeline influence).