Step 1: Purpose.
UNGA Resolution 377A ``Uniting for Peace'' (1950) empowers the General Assembly to recommend collective measures when the Security Council cannot act due to veto deadlock.
Step 2: Year check.
1945 is UN founding; 1954 and 1991 involve other UN events.
Step 3: Conclude.
\[
\boxed{\text{1950 (Option B).}}
\]