TOEFL Reading: ETS-TOEFL阅读机经 - XPY36KD7P2OS760EL$

In paragraph 1, why does the author mention that "most Greek and Roman settlements were laid out on the grid system" A. To show how they resembled one another in terms of their layout B. To support the claim that city planning had a long history in Europe C. To help explain why cities of Renaissance and Baroque design were typically laid out in the form of a grid D. To contrast the sophistication of Greek and Roman urban design with the simplicity of the urban design of the Renaissance and Baroque periods