Explanation/Reference:
Identity Store: It is directory server to perform the authentication. It contains user name , password and groups membership information .When a user name and password combination is entered at log in, the authentication provider searches the identity store to verify the credentials provided.
See figure below.

Incorrect answers:
A: Policy Store: Contains the definition of Application Roles, Application Policies, and the mapping between them.A policy store can be file-based or LDAP-based.Oracle Business Intelligence permissions are granted by mapping users and groups from the identity store to Application Roles and permission grants located in the policy store.
B: Credential Store: It is responsible for securely storing and providing access to credentials required by Oracle Business Intelligence Applications components internally.For e.g, SSL Certificates stored here.

Download and installation of the client
The client install executable is available for download from the More Products menu in Oracle BI Interactive Dashboards and Oracle BI Answers.
See picture below.

Metadata Repository Builder's Guide http://download.oracle.com/docs/cd/E21764_01/bi.1111/e10540/toc.htm http://download.oracle.com/docs/cd/E21764_01/bi.1111/e10540.pdf
Setting an Implicit Fact Column in the Subject Area For each subject area in the Presentation layer, you can set an implicit fact column. The implicit fact column is added to a query when it contains columns from two or more dimension tables and no measures. The column is not visible in the results. It is used to specify a default join path between dimension tables when there are several possible alternatives or contexts.

Oracle Business Intelligence Enterprise Edition (OBIEE) Security is managed through:
a) BI Server Security Manager accessed through the BI Server Administration Tool.
*Set permission to business model, tables, columns and subject areas
*Specify filters to limit data accessible by users
*Set authentication options
b) BI Presentation administration accessed through Presentation Web Services.
*Manage Web groups and users
*Set Permissions for Web Catalog items
*Manage privileges and rights given to groups and users
*Control access to dashboards c) Catalog Manager.
*Set permission for Web Catalog items (Dashboards and Dashboards pages)