Final answer:
Activity-based costing is suitable for both internal and external reporting, job order costing and variable costing are appropriate for internal reporting, and process costing is suitable for external reporting.
Step-by-step explanation:
Costing Methods for External and Internal Reporting -
A. Activity-based costing: This costing method is appropriate for both external and internal reporting. Activity-based costing allocates costs to specific activities or cost drivers, providing a detailed analysis of costs for decision-making.
B. Job order costing: This costing method is appropriate for internal reporting. Job order costing is used to track costs for individual custom products or services.
C. Variable costing: This costing method is appropriate for internal reporting. Variable costing only includes variable manufacturing costs and treats fixed manufacturing costs as period costs.
D. Process costing: This costing method is appropriate for external reporting. Process costing is used when products pass through multiple processes and the costs are averaged across all units produced.