题目选项分析

Ten years ago, the Salisbury City Council passed the Culinary Bill, new legislation to protect the interests of local non-franchise restaurants. Of the 120 local non-franchise restaurants in Salisbury today, 85 opened during the last ten years. Clearly the Culinary Bill has caused a surge in the number of local non-franchise restaurants operating in Salisbury over the past ten years.

Which of the following is an assumption on which the argument depends?

【选项】All economic indicators suggest that household incomes in Salisbury have risen substantially over the past ten years.