Dropping role A does not affect the SELECT privileges granted to roles B and C on the table DB1.S1.T1. According to the Snowflake documentation, dropping a role revokes all privileges granted to the role, but does not revoke any privileges granted by the role. Therefore, the OWNERSHIP privilege on the table DB1.S1.T1 will be revoked from role A, but the SELECT privileges granted by role A to role B and by role B to role C will remain. The GRANTED_BY column will still show the original grantor of the privilege, not the ACCOUNTADMIN role.