A company has multi-currency projects and tasks. What is the hierarchy in which the currency attributes are allocated to a transaction?

Note: Setting up Multi-Currency Transactions To set up your system to process multi-currency transactions, perform the following steps:
* Implementation Options Use the Currency Implementation Options to control the default values for currency attributes at the operating unit level. Oracle Projects uses the currency attributes to calculate currency exchange rates. See: Currency Implementation Options.
* Currency For each project for which you want to process multi-currency transactions, set up the Currency options in the project and task options window. This option enables you to enter default currency attributes for a project. See: Currency, Oracle Projects Fundamentals.
* Cross Charge You can use the Cross Charge Options to specify whether the project can accept charges from other operating units. See: Cross Charge Setup, Oracle Projects Fundamentals.
* Task Currency and Cross Charge Options
* You can use the Task Currency and Cross Charge Options to override the costing currency conversion attributes and cross charge options in a lowest task. See: Currency, Oracle Projects Fundamentals and Cross Charge Setup, Oracle Projects Fundamentals.
* Transaction Entry and Transaction Import During Transaction Entry and Transaction Import, you can override the project and task currency attributes. See: Entering Expenditures, Oracle Project Billing User Guide and Currency Conversion Attributes for Imported Transactions, Oracle Projects APIs, Client Extensions, and Open Interfaces Reference.
Reference: Oracle Projects Implementation Guide