A developer wants to import the data or different instances.

When importing data between instances, focusing on significant and impactful data types is essential:

Option B (Catalog): Includes all product listings, descriptions, categorizations, and relationships. It's crucial for the eCommerce operation, directly affecting site navigation and customer experience.

Option C (Customers): Customer data import is essential for maintaining continuity in customer relationships, access, and personalization across platforms.

These data types are fundamental to the functioning of an eCommerce site and ensure that essential operational data is consistent across different environments or platform migrations.