Meiyu from mid-June to early July every year mainly occurs in () A. Southeast coast B. Middle and lower reaches of the Yangtze River C. North China D. Northeast China.

Meiyu weather refers to the rainy season from mid-June to early July in early summer, and the middle and lower reaches of the Yangtze River are often continuous. Because this is the season when plums are yellow and ripe, people are used to calling it "Meiyu season". Due to the long meiyu time, high air humidity and more mildew, the meiyu weather is characterized by long-term continuous rainfall, high relative humidity, short sunshine time, low ground wind, overcast clouds and continuous rainfall.

Therefore, choose: B.