Final answer:
The condition "Speed of referral is the principal advantage" aligns with option B (Competitor Inventory), as both firms compete for customers and try to balance their market share.
Step-by-step explanation:
The condition stated in the question is "Speed of referral is the principal advantage." To determine whether it aligns with option A (Case Examining) or option B (Competitor Inventory), we need to analyze the information provided. In the given context, the passage talks about two competing firms on Main Street and their strategies to capture customers. It mentions that each firm wants to capture the maximum number of customers, leading to a state of equilibrium where both firms capture nearly equal customers. This scenario suggests that option B (Competitor Inventory) is true as both firms compete for customers and try to balance their market share.