"A node type validation is a data object that enables you to define rules for validating nodes of a specific node type. You can use node type validations to check for conditions such as: Property values are in a certain format; Start date occurs before end date; Hierarchy levels match specific node types." The other options are not examples of node type validations.

According to the Oracle documentation, application registration is the process of creating an Enterprise Data Management Cloud application and defining its configuration. During application registration, you select an application type and the system generates default data objects based on your selections in the registration wizard. The system does not generate connections to external applications, import external application data, or load dimension data from flat files during application registration. These tasks are performed separately after the application is registered.

Permissions secure access to applications, dimensions, data chain objects, and data. There are four levels of permissions: Owner, Data Manager, Participant (Write), and Participant (Read). When you grant a permission at a higher level, such as Owner, it includes all of the permissions at lower levels. For example, if you grant a user Owner permission on an application, they also have Data Manager and Participant permissions on that application. Permissions assigned to a dimension also apply to the hierarchy sets and node types that they contain. By default, when you assign the Participant permission to a user or group, their data access is set to Read. Reference: Working with Permissions - Oracle Help Center1

Lookup sets are used to associate source values, or keys, with target values that can be used in expressions for deriving properties or transforming properties in node type converters. You can configure keys and values in a lookup set for one or more applications. Lookup sets are not created during application registration, but rather as separate objects that can be shared across applications. Lookup sets are not used to group and filter nodes, but rather to map values between different applications or perspectives. Reference: Working with Lookup Sets - Oracle Help Center2

This option is correct because when you define an approval policy at the dimension level, it applies to all the node types and hierarchy sets that belong to the dimension. You can also define approval policies at the node type or hierarchy set level to override the dimension level policy.
Reference:
https://docs.oracle.com/en/cloud/saas/enterprise-data-management-cloud/edmra/creating-approval-policies.html