A Mass Quick Action is specifically designed for the described scenario. It enables users to select multiple records from a list view (up to 100 at a time) and perform a bulk update, such as changing the 'Case Type' field. This provides an efficient, single-click solution for managers to update up to 75 cases simultaneously, directly addressing the requirement for a productivity tool that works on list views for multiple records.

A. Run a macro on each case: Macros automate a sequence of actions on records, typically one at a time. While a bulk macro is possible, it is less efficient for a simple, single-field update than a Mass Quick Action.

C. Use a keyboard shortcut: Keyboard shortcuts are used for navigating the console interface and performing actions on the currently focused record, not for executing bulk updates on multiple records selected in a list view.

1. Salesforce Help - Set Up a Mass Quick Action: "Mass quick actions let users create or update up to 100 records at a time from a list view... For example, you can create a mass quick action that lets users close one or more cases..." This directly supports using a Mass Quick Action for updating multiple cases from a list view.

2. Salesforce Help - Considerations for Mass Quick Actions: "You can use mass quick actions on up to 100 records at a time in a list view." This confirms the tool's suitability for the required scale of updating 75 cases.

3. Salesforce Help - Salesforce Macros: "A macro is a set of instructions that tells the system how to complete a task... Macros are great for tasks that agents do over and over again." This highlights that macros are for a sequence of steps, making a Mass Quick Action a more direct tool for a single bulk update.