Exam Certified Platform App Builder topic 1 question 505 discussion

Cant be A as it says delete from Sales rep profile when its the Sales Team deleting Cant be B as from the question it sounds like the need to delete is still needed Cant be D as VD rules only work on the SObject that they're defined on So gotta be C

The D would be the most practical in a real-life scenario. However the validation rule by itself wouldn't be enough as the answer suggests, it would need a field on the Account object. In my opinion the best option would be to create a rollup summary field on the Account object that shows the number of open opportunities associated and reference it in a validation rule. However as the answer doesn't say that, the only option that makes sense is the Apex trigger (C).