The correct answer is A. Quick Action on the Account object.

Universal Containers wants users to create Opportunity records related to an Account, with many Opportunity fields automatically populated from the Account and some fields entered by the user. The best solution is an object-specific Quick Action on Account that creates an Opportunity. Object-specific actions run in the context of the parent record, and predefined field values can automatically populate fields to make record creation faster and more consistent.

C is incorrect because a Quick Action on Opportunity would not naturally start from the Account context. B and D are incorrect because assignment rules are not used for creating related Opportunities or prepopulating fields.

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