In general, the monthly billing for database replication is proportional to which variables?

Snowflake charges for database replication based on two categories: data transfer and compute resources1. Data transfer costs depend on the amount of data that is transferred from the primary database to the secondary database across regions and/or cloud service providers2. Compute resource costs depend on the use of Snowflake-provided compute resources to copy data between accounts across regions1. Both data transfer and compute resource costs are proportional to the frequency and amount of changes to the primary database as a result of data loading or DML operations3. Therefore, the answer is A and B. The other options are not directly related to the replication billing, as the frequency of secondary database refreshes does not affect the amount of data transferred or copied4, and the number and size of warehouses defined in the primary account do not affect the replication process5.