Choose the correct variant. You should take an umbrella. It _______ today.

{"correct_option"=>"is going to rain", "explanation"=>"The correct sentence is 'You should take an umbrella. It is going to rain today'. The phrase 'is going to' is used to talk about the future when there is a present indication or evidence that something will happen. In this case, the suggestion to take an umbrella is the present evidence that rain is expected. The other options are grammatically incorrect. 'will be rain' is not a valid English construction, 'rains' is a simple present tense, and doesn't fit the context of future intention, and 'is going to raining' is grammatically incorrect."}