The feature that the app builder should use to create easy access to the document is a custom detail page link on the Contract object. A custom detail page link is a type of custom button or link that can display a URL or execute JavaScript when clicked. The app builder can create a custom detail page link on the Contract object that displays the pricing guidelines document in a new window or tab. Option A is incorrect because a quick action on the Contracts object is not suitable for this requirement, as quick actions are used to create or update records, log calls, send emails, or launch flows. Option B is incorrect because a quick action on the Account object is not suitable for this requirement, as quick actions are not related to the Contract object. Option C is incorrect because a custom detail page link on the Account object is not suitable for this requirement, as custom detail page links are not related to the Contract object.