Select the most appropriate option to fill in the blank and make a grammatically correct sentence.

Timely alerts about floods in Bhutan ______ a blessing to Indian villages.

have proved

The most appropriate option to fill in the blank is have proved.

The sentence is about how timely alerts about floods in Bhutan have proved to be a blessing to Indian villages. The verb "have proved" is in the present perfect tense, which is used to talk about actions that happened in the past but have a connection to the present. In this case, the timely alerts about floods in Bhutan have had a positive impact on Indian villages in the past, and they continue to do so in the present.

The other options are not as appropriate.

• Are proved is in the present tense, which does not make sense in the context of the sentence because the action of proving something happened in the past.
• Is proved is also in the present tense, and it is not grammatically correct to use the singular verb "is" with the plural noun "timely alerts."
• Has proved is also in the present perfect tense, but it is not the most appropriate option because it does not emphasize the ongoing impact of the timely alerts about floods in Bhutan.