Which of the following statements is true?

In activity$-$based costing, all manufacturing costs must be included in product costs.

Activity$-$based costing is a costing method that is designed to provide managers with product cost information for internal decision$-$making.

Activity$-$based costing is best proposed, designed and implemented by the accounting department without requiring the time of busy managers.

A traditional cost system is generally easier to set up and run than an activity$-$based costing system.