The correct answer is D. Job costing.
Job costing is a costing system that is used to track the costs of individual jobs or batches of products. It is a very detailed costing system that is used in industries where each job or batch is unique.
In the printing of wedding invitation cards, each job is unique, as the cards are customized for each individual wedding. This means that job costing is the most appropriate costing system to use.
Process costing is a costing system that is used to track the costs of a continuous process. It is a less detailed costing system than job costing, and it is used in industries where products are produced in a continuous flow.
Unit costing is a costing system that is used to track the costs of individual units of product. It is a very simple costing system, and it is used in industries where products are produced in large quantities.
Contract costing is a costing system that is used to track the costs of individual contracts. It is a similar to job costing, but it is used in industries where contracts are long-term and complex.
In conclusion, the most appropriate costing system for the printing of wedding invitation cards is job costing. This is because each job is unique, and job costing is a very detailed costing system that is designed to track the costs of individual jobs.