Answer:
Around four years and three months
Explanation:
The Danube, which is the second-longest river in Europe. The Loire, which flows through France and splits the country midway. The Elbe, which flows through Germany and the Czech Republic and links popular destinations. The Rhine, which streams 766 miles to the Netherlands and ends in the North Sea. The Volga, which is the longest river in Europe.
The subject of science is very broad. With that being said, I think there is no official regulatory board that decides the branches of science. Scientific developments are products of joined efforts of different scientists. These scientists could rebuke another's work provided there is evidence. As long as the theory is generally accepted by the scientists and no one rebukes it effectively, then it is a generally accepted fact and everyone adapts it.
Hence, the answer is B.
