Answer: D) economies of scale.
Step-by-step 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.