The author’s argument about urban green roofs would be weakened if

• A. Green roofs only provide insulation, not stormwater management.
• B. Green roofs gained public support.
• C. There is strong evidence of energy savings.
• D. Costs of installation have fallen.

Answer: (A)

This item tests how the strength of an argument about a policy benefit depends on the range of benefits it asserts. If the argument is that urban green roofs are valuable because they offer multiple advantages—such as insulation and stormwater management—then showing that one of those benefits is not actually provided weakens the overall case. If green roofs only give insulation and do not help with stormwater management, a key urban justification—reducing runoff and flood risk—is missing, making the proposal less persuasive to decision makers and stakeholders. The other potential supports (public backing, evidence of energy savings, lower installation costs) would either strengthen the argument or make it more appealing, not weaken it.