Explanation/Reference: https://docs.servicenow.com/bundle/orlando-application-development/page/integrate/web-services/ reference/r_AvailableWebServices.html

https://docs.servicenow.com/bundle/tokyo-application-development/page/app-store/dev_portal/API_reference/gl

The data type of a field determines the format, validation, and display of the field value on a form. When selecting a data type for a field, you should consider the purpose and function of the field. The statements A, C, and D are correct for selecting a data type for a field. For example:
* Use the Choice data type to limit options in a field: The Choice data type allows you to create a field that has a predefined set of options for the user to select from. The options can be displayed as a drop-down list, radio buttons, or checkboxes. For example, you can use the Choice data type for a field that indicates the priority of a task.
* Use the Phone Number data type to automate phone number data validation: The Phone Number data type allows you to create a field that accepts and validates phone numbers. The field will automatically format the phone number according to the user's locale and country code. For example, you can use the Phone Number data type for a field that stores the contact number of a user.
* Use the string data type for a free-form text field: The string data type allows you to create a field that accepts any text input from the user. The field can have a maximum length of 255 characters. For example, you can use the string data type for a field that captures the short description of an incident.
The statement B is not correct for selecting a data type for a field. There is no Data data type in ServiceNow.
To enter the date and time of day, you should use the Date/Time data type. The Date/Time data type allows you to create a field that accepts and displays a date and time value. The field will use a calendar widget and a time picker to help the user enter the value. For example, you can use the Date/Time data type for a field that records the due date of a task.
References:
* [Field types]
* [Date/Time field type]

Application Access is a feature that allows you to control the access level of other application scopes to your application's data tables. You can use Application Access to control the following database operations:
Create: This operation allows the user to create new records on the table. You can enable or disable this operation by selecting or clearing the Can create option.
Delete: This operation allows the user to delete existing records on the table. You can enable or disable this operation by selecting or clearing the Can delete option.
Read: This operation allows the user to view the records on the table. You can enable or disable this operation by selecting or clearing the Can read option.
Write: This operation allows the user to modify the records on the table. You can enable or disable this operation by selecting or clearing the Can write option.
The one database operation that cannot be controlled with Application Access is Query. Query is not an operation, but a method of the GlideRecord class that is used to retrieve records from the database on the server-side. Query is not part of the Application Access rules, but it is affected by the Access Controls and the user's roles.
Reference:
Application Access
[GlideRecord methods]