I'm quibbling with this question. In order for B to be correct, it seems as if we have to assume that the size of the population and economy is meaningfully linked to the returns on the city's investment in an advisor. This assumption isn't present in any form in the stimulus.

I still think this is the correct answer choice, as the others are less relevant to the stimulus, but B could also as easily be irrelevant, if we ultimately find out the population and size of the economy are irrelevant to the return on investment.