Final answer:
Efficiency in customer service refers to both doing the right things for the desired outcomes and utilizing the least resources while doing so, meaning the correct answer is c) Both a and b.
Step-by-step explanation:
When discussing the con of optimal customer service contributing to the firm's welfare, the term efficiency in customer service refers to both doing the right things to achieve desired outcomes and doing things right with the least amount of resources. The correct answer would be c) Both a and b. Efficiency in the broader economic sense, particularly within the demand and supply model, means that the economy is maximizing benefits from its scarce resources, achieving all possible gains from trade, and ensuring that an optimal amount of each good and service is being produced and consumed. This aligns with the maximization of production and the organization of an economy in a way that productive and allocative efficiency are both achieved, as seen when profit-maximizing firms and utility-maximizing consumers interact in perfectly competitive markets.