The manager should configure the template once it's moved to the shared folder to select the View and Send permission option1. This option allows the manager to grant access to the template to other business units, but prevent them from making any changes to the template content or layout1. This way, the manager can ensure that the template remains consistent and on-brand across all business units.
Selecting the Edit Globally permission option is not the correct answer, as it does not ensure that the template remains on-brand. This option allows the manager to grant access to the template to other business units, but also allow them to make changes to the template content or layout1. This way, the manager may lose control over the template and risk having different versions of the template across different business units.
Making a copy in each business unit to allow local edits is also not the correct answer, as it does not ensure that the template remains on-brand. This option allows the manager to create separate copies of the template for each business unit, but also allow them to make changes to their own copy of the template2. This way, the manager may have difficulty managing and updating multiple copies of the template across different business units. References := 1: Share Content Across Business Units - Salesforce 2: Content Builder Best Practices - Salesforce