Comprehensive and Detailed Explanation

The correct answer is B --- Salesforce Data Entry Source on the Contact Object.

The Salesforce Data Entry Source allows you to trigger journeys based on new or updated Salesforce records.

Since you are trying to trigger based on new contacts (and Contacts are tied to Accounts in B2B), you would configure the journey to listen for Contact creation or update events.

Why others are wrong:

A: Salesforce Campaign Entry Source is tied to Campaign Members, not Contacts.

C: Salesforce Data Entry Source on Account Object isn't typically used to drive Contact-specific Journeys --- Contacts should be the focus.

D: Welcome Email Configuration is not relevant for Journey Builder --- it's for basic email sends.

Exact Extract from Salesforce Official Documentation:

Salesforce Help --- Salesforce Data Entry Source:

'Use Salesforce Data Entry Sources to start a journey when records on standard or custom Salesforce objects like Contacts, Leads, or Opportunities are created or updated.'

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

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