A market maker system is best described as multiple market makers competing by displaying bids and offers, which makes choice B correct. Market makers are firms (or participants) that stand ready to buy and sell a security on a regular and continuous basis by quoting two-sided markets—bid (what they will pay) and ask/offer (what they will sell for). In many market structures, multiple market makers post competing quotes, and the best displayed prices help form the national best bid and offer (NBBO) and promote liquidity and price discovery.

Choice A is closer to the concept of a single designated liquidity provider (like a specialist model historically), but even where “designated market makers” exist, modern systems typically still involve competition and additional liquidity providers. Choice C is incorrect because negotiation between individual participants through a designated market maker is not the defining mechanism of a market maker system; market makers post continuous quotes rather than serving as a negotiation channel for each trade. Choice D is also incorrect because orders are not generally sent to one market maker “for review” before being displayed; orders can be routed to various venues, displayed in order books, or executed against quotes depending on market structure.

For the SIE, the key takeaway is that market makers support liquidity by committing capital and quoting markets, and that competition among multiple market makers improves execution quality through tighter spreads and more robust depth. Understanding how bids/asks are displayed and how market participants interact with liquidity providers is central to market structure and trading knowledge.