When balancing an intercompany journal, Oracle Fusion Cloud will first look for a primary balancing segment rule that matches the provider and receiver primary balancing segment values. If such a rule exists, it will be used to generate the intercompany receivables and payables accounts. If not, Oracle Fusion Cloud will look for a chart of accounts rule, then a legal entity-level rule, and finally a ledger-level rule. The primary balancing segment rule has the highest priority and the ledger-level rule has the lowest priority. References:
* Overview of Intercompany Balancing Rules
* Intercompany Balancing Rules
* Troubleshooting Guide For Intercompany Balancing
* Example of Generating Intercompany Receivables and Intercompany Payables Accounts

Balances cubes are multidimensional databases that store financial balances for interactive reporting and analysis. A balances cube is created for each unique combination of ledger and currency, and it contains dimensions such as chart of accounts segments, periods, scenarios, and other user-defined attributes. New dimensions can be added to a balances cube by using the Manage Balances Cube Dimensions task in General Ledger. Balances cubes are updated automatically when journals are posted in General Ledger, and they can also be refreshed manually by using the Refresh Balances Cube task. Balances cubes are not affected by the Translation or Revaluation processes, as these processes only update the balances tables in General Ledger. References:
* Overview of Oracle General Ledger Balances Cubes1
* Considerations for General Ledger Balances Cubes2
* Overview of Oracle Essbase Balances Cubes3

According to Oracle documentation, when there is a business requirement for a subsidiary company to report to the parent company on a monthly basis with different currencies and no requirement to have daily balances, you should recommend Balance level as the data conversion level. A Balance level data conversion level enables you to translate balances from one currency to another at month-end or quarter-end for reporting purposes. A Balance level data conversion level minimizes the data stored in the reporting currency because it does not store daily balances or journal details. Therefore, option D is correct. Option A is incorrect because a Subledger level data conversion level stores daily balances and journal details in the reporting currency.
Option B is incorrect because a Journal Level data conversion level stores journal details in the reporting currency. Option C is incorrect because an Adjustment only level data conversion level does not translate balances from one currency to another. Option E is incorrect because a Spreadsheet level data conversion level does not exist.