It is widely accepted that English is the global language of modern times. About three decades ago,French was recognized as the language of diplomacy（外交）,and German was considered the language of science and technology.English now dominates（主导）not only as

It is widely accepted that English is the global language of modern times.
About three decades ago,French was recognized as the language of diplomacy（外交）,and German was considered the language of science and technology.English now dominates（主导）not only as the language of science but also diplomacy,computing,and tourism.Today,in terms of native speakers,Mandarin Chinese is the world′s
largest language.
Yet there are people who believe that China will become the most powerful country in the world.Some have?even fixed the date as early as the year 2020.At present,while English is more widely spoken than any other?language,there are more people who speak Chinese than English due to the large population in China alone.If China?does become a world power,there is no doubt that this language will spread worldwide.
As the controversy over which language will become dominant in the world continues,there are many who feel?that the dominance of English is unique and irreversible（不可逆的）.However,a separate study from David Graddol′s suggests that English′s dominance in the scientific area will continue.There is also an argument that the?English language would be changed greatly by 2020 for various reasons.With the possibility of China rising as a?world power,Mandarin could definitely challenge the dominance of English as a global language.

What does controversy in the last paragraph probably mean?

A.Plan.
B.Argument.
C.Conditoin.
D.Goal.