During upgrades, what is the recommended approach to minimize risk and ensure compatibility?

During upgrades, what is the recommended approach to minimize risk and ensure compatibility?

• A. Back up data, verify customizations, test in sandbox, ensure compatibility of templates/clauses, perform staged migrations.
• B. Upgrade directly in production without any tests.
• C. Only test the templates; ignore clauses.
• D. Disallow any migration and stay on old version.

Answer: (A)