Once the files are copied into a table, they cannot be copied again in the next 64 days because of the files’ metadata. If this option is true, it loads all files, regardless of whether they’ve been loaded previously and have not changed since they were loaded. https://plazagonzalo.medium.com/snowflake-snowpro-data-loading-f88afaef7eb9#cf88

D is correct

what s the difference between B) and D) the meaning is the same, only data from new files will be added...

D is correct Loading Older Files¶ This section describes how the COPY INTO <table> command prevents data duplication differently based on whether the load status for a file is known or unknown. If you partition your data in stages using logical, granular paths by date (as recommended in Organizing Data by Path) and load data within a short period of time after staging it, this section largely does not apply to you. However, if the COPY command skips older files (i.e. historical data files) in a data load, this section describes how to bypass the default behavior. https://docs.snowflake.com/en/user-guide/data-load-considerations-load#executing-parallel-copy-statements-that-reference-the-same-data-files

D - only the new files will be appended B - SF doesn't know which customer is new (COPY doesn't care about the meaning of data, care about files (file names) which are new (no kept in metadata as loaded)

D is correct answer

only the new files will be appended

https://docs.snowflake.com/en/user-guide/data-load-considerations-load.html#executing-parallel-copy-statements-that-reference-the-same-data-files

D - COPY command maintains historic load metadata with target table , so day 1 , 10 files will will not be loaded again

https://community.snowflake.com/s/question/0D50Z00009T3JWXSA3/upload-data-to-table-and-avoid-duplicated-data-rows