Final answer:
The opening of a new subway stop increases the number of potential consumers for the local bagel shop, which exemplifies the 'Number of Consumers' factor influencing demand.
Step-by-step explanation:
The factor influencing demand exemplified in the scenario "A new subway stop opened, and sales at the local bagel shop are up" is Number of Consumers. When a new subway stop opens, it increases the number of potential customers passing by the Bagel shop, which could consequentially increase the demand for the bagels. This situation does not directly relate to expectations, complements, or consumer tastes, but simply the increased foot traffic that comes with a new subway stop.