Exam Platform-App-Builder Topic 4 Question 178 Discussion

A clean build puts the rule where Salesforce evaluates it. In this case, Choose B. One Master-detail relationship on Contact and one Master-detail relationship on Solar Project. Master-detail relationships create ownership, security, and lifecycle dependency between parent and child records. A junction object uses two master-detail relationships to represent a many-to-many model.
The stem gives enough detail to reject surface-level fixes. Salesforce should be configured so the behavior is enforced or rendered by the feature designed for it. When the requirement touches Data Modeling and Management, the builder should avoid crossing into a different layer unless there is a real platform limitation.
The selected answer follows that discipline and creates the least surprising result for admins and users.
The remaining answers do not control the same Salesforce behavior. A (Two Master-detail relationships on a new custom object) would be fragile here because Master-detail is powerful, but it is wrong when the records need independent ownership or when the child-parent direction is reversed. C (Two Lookup relationships on a new custom object) is only a partial match because A lookup relationship is more loosely coupled and does not provide every master-detail behavior, especially native roll-up behavior. D (One Lookup relationship on Contact and one Lookup relationship on Solar Project) misses the mark because A lookup relationship is more loosely coupled and does not provide every master-detail behavior, especially native roll-up behavior. The result is a cleaner app design because the behavior is handled by the feature Salesforce built for that purpose.
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