An American scientist has won the Nobel Prize for Physics.

The Nobel Prize for Physics has been won by an American scientist.
The Nobel Physics Prize has been won by an American scientist.
The Nobel Prize has been won by an American scientist.
The Nobel Prize for Physics is won by an American scientist.

The correct answer is: A. The Nobel Prize for Physics has been won by an American scientist.

The other options are incorrect because they use the present tense, which is not grammatically correct in this context. The Nobel Prize is awarded once a year, so it is correct to say that it has been won by someone, rather than that it is won by someone.

Additionally, the Nobel Prize is a specific prize, so it is correct to refer to it as the Nobel Prize for Physics, rather than the Nobel Physics Prize or the Nobel Prize.

Finally, the Nobel Prize is awarded to an individual, rather than to a group of people, so it is correct to say that it has been won by an American scientist, rather than that it has been won by American scientists.