Satellite cloud pictures usually show the ocean in blue, land in green and cloudy and rainy areas in white. When Beijing is green, it means that the Beijing area was (

A. It's sunny in the blue-green area covered by satellite cloud pictures, so it's right.

B There is rainy weather in the white covered area on the satellite cloud picture, which does not meet the meaning of the question.

C. The weather from cloudy to sunny can't be seen on satellite cloud pictures, and can only be represented by weather symbols.

D The weather from sunny to cloudy can't be seen on satellite cloud pictures, and it can only be represented by weather symbols, which doesn't meet the meaning of the question.

So choose: a.