Which builder’s solution is right?

This customer was concerned that removal of an unused kitchen chimney breast on the ground floor of his property had left the one above it unsupported, and he had been getting different advice from every builder he spoke to. We were able to confirm that the less expensive options of RSJ or gallows brackets were sound in his case, while cautioning him that that a bulkhead for the supporting downstand  would probably lead to a small loss of space in the kitchen.