Critical Reasoning (CR) | Re: As a construction material, bamboo is as strong as steel and

Dear experts,

Could you please explain why B is correct. In order B to explain the except situation above we should make assumption which, I think ,requires far more assumption than required in any GMAT CR question. Also, it is not everyone's common sense that highly valued land is used primarily for multistorey buildings. One, for example, could argue that highly valued lands is occupied by wealthy people who constructed mansions or there's not any city-like (not sure there's such a word