Explanation
The feature that the app builder should use to allow users to create the opportunity is a quick action. A quick action is a type of custom button or link that can create or update records, log calls, send emails, or launch flows from a record page or a global menu. The app builder can create a quick action on the account object that creates an opportunity record with pre-populated fields. Option B is incorrect because a default action is not a valid term, but rather a standard action that appears on every record page by default, such as Edit or Delete. Option C is incorrect because a custom button is not suitable for this requirement, as custom buttons can only display a URL or execute JavaScript when clicked. Option D is incorrect because a custom link is not suitable for this requirement, as custom links can only display a URL or execute JavaScript when clicked.

A geolocation field can be used to capture the coordinates of a location in latitude and longitude. This field type can also be used in reports, formulas, validation rules, and Apex

Explanation
To insert a list of 25,000 records using deduplication for the Race_Track__c custom object, an app builder should use Data Loader. Data Loader is a tool that allows users to insert, update, delete, or export large amounts of data in Salesforce. Data Loader can also perform deduplication by matching records based on external ID fields or Salesforce record IDs. [Source]