Because each individual franchise owner needs to add their own customized local message layered onto the corporate-controlled campaign, each franchisee requires a distinct level of content editing access and localized content ownership that a single shared child Business Unit cannot cleanly provide, since a shared BU would mix every franchisee ' s local edits together without separation. A dedicated child Business Unit for each franchise owner gives every location its own isolated content space to build and manage its local message customization, while the parent Business Unit retains centralized ownership and control of the core marketing messaging and the master subscriber lists — those master assets can be built once at the parent level and shared down to each child BU via Shared Content/Shared Data Extensions, preserving corporate control while still enabling individual localization. Option A ' s single shared child BU across all franchisees would not adequately separate each owner ' s individual local-message customization work. Option B, a single Business Unit for the whole franchise network, provides no structural separation at all between corporate assets and franchisee-level customization. Option D similarly lacks true BU-level isolation, relying only on folder sharing within one account structure. Reference: Business Unit Hierarchy, Franchise/Multi-Location Marketing Cloud Architecture.