Final answer:
Mass production techniques significantly reduce the per unit production costs of automobiles, making them available at economical prices. Therefore, the correct option is A.
Step-by-step explanation:
The goods that are available at economical prices because of the use of mass production techniques are automobiles. When it comes to automobile manufacturing, there are significant economies of scale. As the level of production increases, the average cost of producing each individual unit declines. This allows automobile manufacturers to produce cars at a lower cost, making them more affordable for consumers.