The correct answer is D. None of these.
Marginal costing and absorption costing are two different methods of accounting for costs. Marginal costing only includes variable costs in the calculation of product costs, while absorption costing includes both variable and fixed costs. For decision-making, marginal costing is more suitable than absorption costing because it focuses on the costs that are directly related to the production of a product.
Statement 1 is incorrect because marginal costing and absorption costing are not the same. Statement 2 is incorrect because absorption costing is not more suitable than marginal costing for decision-making. Statement 3 is correct because marginal costing is based on the distinction between fixed and variable costs.