10) Financial intermediaries can substantially reduce transaction costs per dollar

D) economies of scale.

Explanation:

Economies of scale refers to when an entity is able to reduce its total costs as quantities of the good causing the costs increase.

Financial Intermediaries such as Commercial banks, Mutual funds, Investment banks etcetera have a lot of funds available for trade which they use to execute large trades. As a result, the costs on average are lower or them per transaction as opposed to traders executing with lower volumes. For example, when purchasing shares they will be able to negotiate better fees with stockbrokers because they are buying a lot of shares as opposed a single buyer trading.

Your question asks what is a primary concern for Top managers.

The reason why answer choice "B). Deciding which goods a company should produce" is the correct answer is because this is a concern that top managers mostly focuses on.

Top managers are on top of the rankings in an organization, they have a lot of power to make decisions. Of course, top managers want to best for their company, therefore they need to figure out what the company is going to produce. Top managers have the power to choose what goods a company should produce, and that's the reason why it's their primary concern.

They need to make sure that the item that they chose the company to produce will bring back revenue and profit. If a business produces a good and it doesn't sell well, then the company will go out of business. This is why deciding which goods they should produce is a top managers primary concern,