Comprehensive and Detailed Explanation:

The correct answer is C — Query Activity > Data Extension Entry Source > Journey Activities.

A Query Activity can select subscribers who haven't purchased in six months based on date logic.

The results are saved into a Data Extension.

This Data Extension is then used as the entry source into a Journey, which can orchestrate sending across multiple channels (email, SMS, push).

❌Why others are wrong:

A: API Event is not necessary; you already have the data internally.

B: Import Activity is for external file imports; no external file mentioned.

D: Salesforce Entry Event relates to CRM records, not Data Extension queries.

Exact Extract from Salesforce Official Documentation:

Salesforce Help — Data Extension Entry Source:

"Use the Data Extension Entry Source to inject contacts into a journey based on criteria from a query or automation. This supports orchestrating communications across multiple channels."

(Source:https://help.salesforce.com/s/articleView?id=sf.mc_jb_data_extension_entry_source.htm )

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