Comprehensive and Detailed Explanation:

The correct answer is B — Use Tracking Extract, File Transfer, and Import activities from Automation Studio to inject the subscribers into a data extension used as an Entry Source by Journey Builder.

Tracking Extract Activity allows the extraction of bounced or held subscribers’ data (bounce reasons like "Held").

File Transfer Activity moves the extracted file into the Import directory.

Import Activity loads the file into a Data Extension, which can then be used as the entry source for a re-engagement journey via SMS.

❌Why others are wrong:

A: SQL Query only works if the data is already in a Data Extension; Held status bounce data typically resides in Tracking Extracts.

C: CloudPages Entry Source is incorrect — you want an automated process for SMS.

D: API Event would require custom API calls, but there's no mention of development resources.

Exact Extract from Salesforce Official Documentation:

Salesforce Help — Tracking Extract Activity:

"Use a Tracking Extract Activity to pull tracking data, such as bounces or held status, into a file that can be imported into a data extension for use in journeys or reports."

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

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