TOEFL Listening: TPO-TOEFL阅读TPO - EI5048OOPT4_A3ACN$

According to paragraph 4, what can explain the substantial differences in temperature between one area and other within a well-developed heat island? A. The overall size of the heat island that includes the two reasons B. The intensify of the heat island that includes the two areas C. Differences between the two areas in the general level of activity, including traffic D. Differences between the two areas in the insulation materials used in construction