@MicahBustos because B, unlike the rest of the answer choices, doesn't contain a logical flaw.

COL - Cost of Living

CLDT - Consumers Living Downtown

Profits

DTT - Downtown Traffic

If the conditional chain is: COL down --> CLDT up --> Profits up --> DTT down

B is the only answer choice giving us a valid inference: COL down --> Profits up. It really doesn't necessarily matter to this inference that traffic congestion is up or down. If that makes sense?

A --> B

B --> C

C --> D

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A --> D (valid) but so are:

A --> C & B --> D

@tswalker83 The reason I chose B was because I didn't know what to do with the "must" and the "if". So by default, I went with the "if" and switched the suff. and nec. conditions. Of course, that throws off the entire argument. Soooo, I guess my learning moment was the "must" and "if" in the same sentence = generally "must" takes precedence?