An app builder wants to create a formula field on an Account to include data...

The correct answer is B. Unable to reference the child records.

Formula fields can reference fields on related parent records through cross-object formulas. For example, a formula field on Contact can reference Account fields because Account is the parent of Contact. Salesforce Trailhead shows this pattern by inserting Contact | Account | Account Number in a formula on Contact.

However, the reverse direction is not supported in a normal formula field. An Account formula cannot directly reference values from multiple related Contact child records. Since Contacts are child records of Account, the Contact relationship does not appear in the Account formula editor.

A is incorrect because the issue described is about relationship direction, not the number of formula fields.

C is incorrect because Contact and Account do not need a master-detail relationship for this limitation to apply.

D is incorrect because Salesforce formula character limits are separate from this parent-to-child reference limitation. Salesforce documents formula character limits separately.

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