Read the picture "Baicheng City's weather conditions for three consecutive days in summer". The correct answer below is (　) A. The highest average temperature on the 4th B. 5-day temperature differe

Read the picture "Baicheng City's weather conditions for three consecutive days in summer". The correct answer below is (　) A. The highest average temperature on the 4th B. 5-day temperature difference between day and night

A. On October 4th, it was cloudy day and night. Clouds blocked it during the day, so less solar radiation reached the ground and the temperature was not too high. At night, the reverse radiation from the clouds was strong and little heat was lost from the ground. The temperature won't be too low. The average temperature will not be the highest, so it does not meet the meaning of the question;

B. October 5th is a sunny day, with a lot of solar radiation reaching the ground and a high temperature. On a clear day at night, more heat is lost by radiation from the ground and the temperature is low. The temperature difference between day and night is the largest, so it is correct;

C. October 6, it is sunny during the day and the temperature is high, but it is cloudy at night and loses less heat. The average temperature is higher and frost is less likely to occur, so it does not meet the meaning of the question. ;

D. October 5th was a sunny day with a lot of solar radiation reaching the ground and a high temperature. On a clear day at night, more heat is lost by radiation from the ground and the temperature is low. The temperature difference between day and night is the largest. It cannot be a cold front passing through, so it does not meet the meaning of the question.

So choose: B.