Which of the following was true of both the Cuban Missile Crisis and the Berlin Blockade and Airlift?A commom feature of the Berlin Blockade and...

The only possible answer here is C.  You might be tempted
to put B as the answer, but you should not do that.

The
reason that B is not correct is that, in 1948-9 there was not really any chance of a
global nuclear war.  It was not until the end of August, 1949 that the Soviet Union even
conducted a successful nuclear test.  This means that there was absolutely no way that a
global nuclear war could have broken out over the Berlin blockade.  At this point, the
US did have atomic bombs, but it did not have the missile technology to deliver them so
it would have had to rely on bombers.

This means that the
only possible answer is C.  In both cases, there was a high risk of armed conflict
between the US and the USSR.