Comprehensive and Detailed Step-by-Step
UI Action Types:
List banner button: A button that appears in the list view banner, allowing users to perform actions on multiple records or interact with the list itself.
Form button: A button that appears on a form, enabling users to execute server-side or client-side scripts.
Record navigation button: A button used to navigate between records or perform specific actions related to a record.
Why Other Options Are Incorrect:
Option B (Workflow action): This is not a valid UI Action type; workflows are managed separately.
Option D (List choice) and Option E (Form choice): These are not valid UI Action types; they might confuse users with list or form field options instead.
Reference:
ServiceNow Developer Documentation on UI Actions.

Application Access is a feature that allows you to control the access level of other application scopes to your application's data tables. By setting the Accessible from field value to This application scope only, you can restrict the access to your data tables to only your application scope. This means that other application scopes cannot create, read, write, or delete records on your data tables, unless they have explicit permissions through Access Controls or other means.
References:
Application Access
[Application scope]
https://developer.servicenow.com/dev.do#!/learn/learning-plans/rome/new_to_servicenow/app_store_learnv2_securingapps_rome_application_access
https://docs.servicenow.com/bundle/rome-application-development/page/build/applications/concept/c_ExampleDenyingAllDesignAccess.html

https://developer.servicenow.com/dev.do#!/learn/learning-plans/rome/new_to_servicenow/app_store_learnv2_scripting_rome_debugging_client_scripts The following are debugging strategies for client-side scripts, which run in the web browser and manipulate the user interface:
g_form.addInfoMessage(). This is a client-side API that displays an information message at the top of the form.
Field Watcher. This is a debugging tool that displays the current and previous values of one or more fields on a form.
jslog(). This is a client-side API that writes a message to the browser console.
The following is not a debugging strategy for client-side scripts, but for server-side scripts, which run on the ServiceNow platform and manipulate the database:
gs.log(). This is a server-side API that writes a message to the system log. Reference: Client-Side Scripting APIs, Debugging Client Scripts

Application Access is a feature that allows you to control the access level of other application scopes to your application's data tables. By selecting the Allow access to this table via web services option, you can enable other application scopes to access your data tables using web services, such as SOAP or REST. However, the user performing the query via web services must have the correct permissions to access the table's records. The user must have the appropriate roles and access controls to perform the operations on the table, such as create, read, write, or delete.
The other statements are not true when this option is selected. This option does not restrict the ability to delete records via web services, nor does it allow records to be always read. The access to the records depends on the user's permissions and the web service method. This option also does not restrict access only to SOAP web services, but applies to both SOAP and REST web services. Finally, this option is not the only way to enable web service access to the table's records. Even when this option is not selected, users with the correct permissions can use web services to access the table's records, as long as they specify the application scope in the web service request.
Reference:
Application Access
Web service access to scoped applications