【单选题】Einstein's connection with the politics of the nuclear bomb is well known: he signed the famous letter to President Franklin Roosevelt that persuaded the United States to take the idea seriously, and ...
A.
Einstein was not isolated in his postwar effort to prevent nuclear war.
B.
Einstein was isolated from other scientists in his political advocacy.
C.
Einstein was more than once connected with the political world.
D.
It was the only action that dragged Einstein into the world of politics.